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Chapter 12: Cholinergic Drugs Affecting the Autonomic Nervous System Myasthenia gravis (MG)= chronic disease no cure. is a disease that occurs when antibodies attack nicotinic synapses on skeletal muscles, resulting in symptoms of extreme fatigue, double vision, speech impairment, and difficulty che...

Chapter 12: Cholinergic Drugs Affecting the Autonomic Nervous System Myasthenia gravis (MG)= chronic disease no cure. is a disease that occurs when antibodies attack nicotinic synapses on skeletal muscles, resulting in symptoms of extreme fatigue, double vision, speech impairment, and difficulty chewing or swallowing Administration of pyridostigmine (Mestinon, Regonol) or neostigmine stimulates skeletal muscle contraction and helps reverse the severe muscle weakness characteristic of this disease. Diplopia = also known as double vision, is a visual disturbance that causes a person to see two images of a single object instead of one cholinergic agonist Drugs Action: wet, increased PSNS cholinergic crisis, with symptoms such as fever, visual changes, difficulty swallowing, psychomotor agitation, or hallucinations. (Use these similes to remember the signs of “Hot as Hades, blind as a bat, dry as a bone, mad as a hatter.”) Bethanechol (Duvoid, Urecholine)- cholinergic drug and stimulates Parasympathetic stimulation Action: digestive and urinary tracts, where it stimulates smooth-muscle contraction. Use: to treat non obstructive urinary retention in patients with atony (lack of muscle tone) of the bladder. Alerts: Monitor blood pressure, pulse, and respirations before administration and for at least 1 hour after subcutaneous administration. Side effects include increased salivation, sweating, abdominal cramping, and hypotension that could lead to fainting. Atropine is a specific antidote Anticholinergic drugs Patho: are drugs that inhibit the action of the neurotransmitter ACh at cholinergic synapses. Action: Suppressing the parasympathetic division induces symptoms of the fight-or-flight response Effects: tachycardia, CNS stimulation, and the tendency to cause urinary retention in men with prostate disorders. inhibit sweating, which may lead to hyperthermia. (dilation of the pupils), increase in heart rate, drying of glandular secretions, and relaxation of the bronchi (asthma treatment). anticholinergic is muscarinic antagonists benztropine (Cogentin) is prescribed to reduce the muscular tremor and rigidity associated with Parkinson disease Scopolamine (Transderm-Scop) is used to produce sedation and prevent motion sickness Physostigmine- Antidote for anticholinergic toxicity Uses: an indirect-acting parasympathomimetic that inhibits the destruction of Acetylcholine Alerts: slowly over 5 minutes to avoid seizures and respiratory distress. Monitor blood pressure, pulse, and respirations and look for hypersalivation. Effects: bradycardia, asystole, restlessness, nervousness, seizures, salivation, urinary ­frequency, muscle twitching, and respiratory paralysis. Interactions: cholinergic medications and beta blockers. overdose: atropine should be available. Atropine (Atropen) Therapeutic Class: Drug for treatment of bradycardia, antidote for anticholinesterase poisoning Pharmacologic Class: Anticholinergic Uses: blocks the parasympathetic actions of ACh and induces symptoms of the fight-or-flight response. irritable bowel syndrome, to suppress secretions during surgical procedures, to increase the heart rate in patients with bradycardia, and to dilate the pupil during eye examinations. Alerts: Monitor blood pressure, pulse, and respirations before administration and for at least 1 hour after subcutaneous administration. Expected side effects include dry mouth, constipation, urinary retention, and an increased heart rate. Initial CNS excitement may progress to delirium and even coma. Constricted: contraindicated in patients with glaucoma. obstructive disorders of the GI tract, paralytic ileus, bladder neck obstruction, benign prostatic hyperplasia, myasthenia gravis, cardiac insufficiency, or acute hemorrhage. Overdose: Physostigmine is an antidote for atropine poisoning that quickly reverses the coma caused by large doses of atropine. For convulsions barbiturate or diazepam (Valium) may be administered Chapter 13: Adrenergic Drugs Affecting the Autonomic Nervous System Adrenergic receptors are of two basic types, alpha receptors and beta receptors Alpha1 All sympathetic target organs except the heart Constriction of blood vessels, dilation of pupils EX med dopamine Uses: Shock Treatment of nasal congestion or hypotension; causes dilation of the pupil (mydriasis) during ophthalmic examinations Alpha 2 Presynaptic adrenergic nerve terminals Inhibition of release of norepinephrine Treatment of hypertension (HTN) through a centrally acting (CNS) mechanism Beta 1 Heart and kidneys Increased heart rate and force of contraction; release of renin Treatment of cardiac arrest, heart failure, and shock Beta 2 All sympathetic target organs except the heart Inhibition of smooth muscle EX med albuterol Uses: Asthma, COPD Treatment of chronic obstructive pulmonary disease (COPD), asthma, and preterm labor contractions Beta 3 Adipose tissue Urinary bladder Lipolysis Relaxation of the detrusor muscle Treatment of overactive bladder The adrenergic agonists, also known as sympathomimetics, stimulate the sympathetic nervous system and induce symptoms characteristic of the fight-or-flight response. These drugs have clinical applications in the treatment of shock and hypotension. Effects: Cardiovascular effects such as tachycardia, HTN, and dysrhythmias. can induce CNS excitement and seizures. responses that may occur are dry mouth, nausea, and vomiting. Phentolamine is a nonspecific alpha blocker that may be used to immediately lower blood pressure in patients having a hypertensive crisis. Phentolamine is a specific antidote for catecholamine overdose Drug Phenylephrine (Neo-Synephrine, Vazculep) Therapeutic Class: Nasal decongestant; mydriatic drug; antihypotensive Pharmacologic Class: Adrenergic drug (sympathomimetic) Uses: is a selective alpha-adrenergic agonist intranasal administration: constricting small blood vessels in the nasal mucosa. topical administration: dilate the pupil parenteral administration: reverse acute hypotension Alerts: Parenteral administration can cause tissue injury with extravasation. ophthalmic drops may damage soft contact lenses. This drug causes fetal harm Effects: Intranasal use can cause burning of the mucosa and rebound congestion if used for prolonged periods. Ophthalmic preparations can cause narrow-angle glaucoma bradycardia caution in patients with advanced coronary artery disease, HTN, or hyperthyroidism. Anxiety, restlessness, and tremor may occur due to the drug’s stimulation effect on the CNS. Overdose may cause tachycardia and HTN. antidote: phentolamine, Adrenergic antagonists drugs that act by directly blocking adrenergic receptors. By relaxing vascular smooth muscle in small arteries, cause vasodilation, decreasing blood pressure. second use is in the treatment of benign prostatic hyperplasia (BPH), due to their ability to increase urine flow by relaxing smooth muscle in the bladder neck, prostate, and urethra adverse effect: orthostatic hypotension, occurs when a patient abruptly changes from a recumbent to an upright position. Reflex tachycardia, nasal congestion, and impotence are other important side effects that may occur as a consequence of increased parasympathetic activity. Phentolamine is a nonspecific alpha blocker that may be used to immediately lower blood pressure in patients having a hypertensive crisis. antidote for catecholamine overdose Drug Prazosin (Minipress) Therapeutic Class: Antihypertensive Pharmacologic Class: Adrenergic-blocking drug Uses: selective Alpha 1-adrenergic antagonist that competes with norepinephrine at its receptors on vascular smooth muscle in arterioles and veins. rapid decrease in peripheral resistance that reduces blood pressure. Alerts: Give a low first dose to avoid severe hypotension. cause fetal harm Effects: orthostatic hypotension, hypotension can cause unconsciousness about 30 minutes after the first dose. the first dose should be very low and given at bedtime. Dizziness, drowsiness, or lightheadedness may occur. Reflex tachycardia Chapter 17: Drugs for Seizures Drugs for Seizures Epilepsy- neuro disorder w/ recurrent symptoms may include blackouts, fainting spells, sensory disturbances, jerking body movements and temporary loss of memory Seizures- disturbance of electrical activity in the brain may affect consciousness, motor activity, and sensation, different from epilepsy Convulsions specifically refer to involuntary, violent spasms of the large skeletal muscles of the face, neck, arms, and legs. Known causes of seizures: Fever ○ Rapid increase in body temperature may result in a febrile seizure, especially in infants and toddlers. Infectious diseases. ○ Acute infections, such as meningitis and encephalitis, can cause inflammation in the brain. Metabolic disorders. ○ Changes in fluid and electrolyte levels, such as hypoglycemia, hyponatremia, and water intoxication, may cause seizures by altering electrical impulse transmission at the cellular level. Neoplastic disease. ○ Tumors, especially rapidly growing ones, may occupy space, increase intracranial pressure, and damage brain tissue by disrupting blood flow. Trauma. ○ Physical trauma, such as direct blows to the skull, may increase intracranial pressure; chemical trauma, such as the presence of toxic substances or the ingestion of poisons, may cause brain injury. Vascular diseases. ○ Changes in oxygenation—such as those caused by respiratory hypoxia and carbon monoxide poisoning—and changes in perfusion—such as those caused by hypotension, stroke, shock, and cardiac dysrhythmias—may be causes. Eclampsia- severe hypertensive disorder that continues to worsen as pregnancy progresses s/s- seizures, coma, perinatal mortality Mechanisms of Action of Antiseizure Drugs Goal of antiseizure pharmacotherapy is to suppress neuronal activity just enough to prevent abnormal focus from forming or spreading across the cerebrum Antiseizure pharmacotherapy is directed at controlling the movement of electrolytes across neuronal membranes or affecting neurotransmitter balance Five general mechanisms by which AEDs act: ○ An increase in the activity of gamma-aminobutyric acid (GABA) in the brain (increasing influx of chloride ions) ○ Inhibition of the influx of sodium into neurons ○ Inhibition of the influx of calcium into neurons ○ Correcting neurotransmitter imbalance ○ Blocking of glutamate receptors in the brain. GABA is primary neurotransmitter affected by AEDs because it is the primary inhibitory neurotransmitter so an increase in GABA means a decrease in seizure activity Glutamate is the primary excitatory neurotransmitter in the brain so AEDs block these receptors, so they are glutamate antagonist and suppress neuronal firing Drugs That Potentiate GABA Action These drugs mimic the effects of GABA by stimulating an influx of chloride ions through the GABA receptor channel When the receptor is stimulated and chloride ions move into the cell, the abnormal firing of neurons is suppressed and seizure activity may be prevented or terminated. Barbiturates, benzodiazepines, and other GABA-related drugs reduce seizure activity by intensifying GABA action. The predominant effect of GABA potentiation is CNS depression Treating Seizures with Barbiturates These drugs intensify the effect of GABA in the brain and generally depress the firing of CNS neurons. Replaced by other seizure drugs as first line treatment because they have a low safety margin, increased CNS depressive effects, and have a high dependence rate status epilepticus (SE). SE is a medical emergency characterized by a continuous seizure lasting more than 30 minutes, or two or more seizures without full recovery of consciousness ○ IV diazepam or lorazepam (benzos first) for treatment of this conditions Complementary and Alternative Therapies The Ketogenic Diet for Epilepsy ketogenic diet is most often used when seizures cannot be controlled through pharmacotherapy or when there are unacceptable adverse effects to the medications The ketogenic diet is a stringently calculated diet that is high in fat and low in carbohydrates and protein Classification: Valproic Acid Therapeutic use: Treats all seizure types. Controls mania in bipolar disorder. Prevents migraine headaches. Therapeutic Class: Antiepileptic drug Pharmacologic Class: GABA antagonist Valproic acid is a first-line drug for treating many types of epilepsy. Valproic acid is the delayed-release form of the drug given by the oral route. Valproate sodium is the sodium salt of valproic acid given PO or IV. Divalproex sodium (Depakote ER) is a sustained-release combination of valproic acid and its sodium salt treat absence seizures and complex partial seizures. Depakote ER is also approved for the prevention of migraine headaches and mania associated with bipolar disorder. Alerts: Valproic acid is a gastrointestinal (GI) irritant. A Do not mix valproic acid syrup with carbonated beverages because it will trigger immediate release of the drug, which causes severe mouth and throat irritation. birth defects, Effects: sedation, drowsiness, GI upset, and prolonged bleeding time. Other effects include visual disturbances, muscle weakness, tremor, psychomotor agitation, bone marrow suppression, weight gain, abdominal cramps, rash, alopecia, pruritus, photosensitivity, erythema multiforme, and fatal hepatotoxicity. Black Box Warning: May result in fatal hepatic failure, especially in children under the age of 2 years. Liver function tests should be performed prior to treatment and at specific intervals during the first 6 months of treatment. Valproic acid can produce life-threatening pancreatitis and teratogenic effects, including spina bifida. Drug Phenobarbital Therapeutic Class: Antiseizure drug; sedative Pharmacologic Class: Barbiturate; GABA, A receptor agonist Uses: long-acting barbiturate used for the management of a variety of seizures. used to produce sedation and was once used to treat insomnia. Should not be used for pain relief. Can cause epilepsy. Alerts: soft-tissue irritant. Intramuscular (IM) injections may produce a local inflammatory reaction. IV administration is rarely used because extravasation may produce tissue necrosis. Abrupt discontinuation may increase seizure frequency. teratogenic in humans. Effects: Schedule IV drug that may cause dependence. Common side effects include drowsiness, vitamin deficiencies (vitamin D, folate B12 and B9) and laryngospasms. With overdose, phenobarbital may cause severe respiratory depression, CNS depression, coma, and death. Contraindications: glaucoma or prostatic hypertrophy. Overdose: activated charcoal, or hemodialysis. Treatment is supportive and consists mainly of endotracheal intubation and mechanical ventilation. Drug Diazepam (Valium) Therapeutic Class: Antiseizure drug Pharmacologic Class: Benzodiazepine; GABAA receptor agonist Uses: anti seizure therapy, the primary indication for diazepam is status epilepticus. It may also be used to prevent seizures in patients who have received toxic substances or during the acute phase of alcohol or benzodiazepine withdrawal. Tolerance may develop after about 4 weeks. When given IV, effects occur in minutes and its anticonvulsant effects last about 20 minutes. Alerts: When administering IV, monitor respirations every 5 to 15 minutes. Have airway and resuscitative equipment accessible. Causes fetal harm Effects: reserved for short-term seizure control or for status epilepticus. When given IV, hypotension, muscular weakness, tachycardia, and respiratory depression are common. Contradictions: shock, coma, depressed vital signs, obstetrical patients, and infants less than 30 days of age. In tablet form, the medication should not be administered to infants less than 6 months of age, to patients with acute narrow-angle glaucoma or untreated open-angle glaucoma, or within 14 days of monoamine oxidase inhibitor therapy. Drug to drug: should not be taken with alcohol or other CNS depressants because of combined sedation effects. overdose : If an overdose occurs, administer flumazenil (Romazicon), Drug Phenytoin (Dilantin, Phenytek) Therapeutic Class: Antiseizure drug; antidysrhythmic Pharmacologic Class: Hydantoin; sodium influx–suppressing drug Uses:desensitizing sodium channels in the CNS, preventing the spread of abnormal electrical charges in the brain that produce seizures effective against most types of seizures except absence seizures. Phenytoin has antidysrhythmic activity similar to that of lidocaine very narrow range between a therapeutic dose and a toxic dose, patients must be carefully monitored. Alerts: Always prime or flush IV lines with saline before hanging phenytoin as a piggyback because traces of dextrose solution in an existing main IV or piggyback line Use an IV line with a filter when infusing this drug. Phenytoin injectable is a soft-tissue irritant that causes local tissue damage following extravasation. To reduce the risk of soft-tissue damage, do not give IM; inject into a large vein or via a central venous catheter. This drug is a known teratogen Effects: dysrhythmias, such as bradycardia or ventricular fibrillation, severe hypotension, and hyperglycemia. Severe CNS reactions include headache, nystagmus, ataxia, confusion and slurred speech, paradoxical nervousness, twitching, and insomnia. Peripheral neuropathy may occur with long-term use. Phenytoin can cause multiple blood dyscrasias, including agranulocytosis and aplastic anemia. Food warning: Ginkgo may reduce the therapeutic effectiveness of Black Box Warning: The rate of IV Dilantin administration should not exceed 50 mg/min in adults and 1–3 mg/kg/min (or 50 mg/min, whichever is slower) in pediatric patients because of the risk of severe hypotension and cardiac arrhythmias. Careful cardiac monitoring is needed during and after administering IV Dilantin. Overdose: Drug removal may be accomplished by gastric lavage, use of activated charcoal, or laxative. Drug Ethosuximide (Zarontin) Therapeutic Class: Antiseizure drug Pharmacologic Class: Succinimide Uses: Ethosuximide is a preferred drug for managing absence seizures Alerts: Do not abruptly withdraw this medication because doing so may induce tonic–clonic seizures. Effects: Ethosuximide may impair mental and physical abilities. Psychosis or extreme mood swings, including depression with suicidal behavior, CNS effects include dizziness, headache, lethargy, fatigue, ataxia, sleep pattern disturbances, attention difficulty, and hiccups. Other reactions include gingival hypertrophy and tongue swelling. Common side effects are abdominal distress and weight loss. Overdose: Drug removal may include emesis unless the patient is comatose or convulsing. CH19 Drugs for Local and General Anesthesia Drug Propofol (Diprivan) Therapeutic Class: IV anesthetic Pharmacologic Class: N-methyl-D-aspartate receptor agonist Uses: Propofol is indicated for the induction and maintenance of general anesthesia. immediate onset of action and is used effectively for conscious sedation. Alerts: propofol may provide faster onset and deeper sedation. fetal harm Effects: pain at the injection site, apnea, respiratory depression, and hypotension. Contraindications: hypersensitivity reaction to the medication or its emulsion, which contains soybean and egg products. used with caution in patients with cardiac or respiratory impairment. Drug Nitrous Oxide Therapeutic Class: General anesthetic Pharmacologic Class: Inhalation gaseous drug Uses: analgesia caused by suppression of pain mechanisms in the CNS. low potency short surgical or dental procedures always combined with oxygen (25 to 30%) and is administered in a semi closed method through a tube or by mask. Alerts: Short-duration anesthesia using nitrous oxide has not been shown to cause fetal harm. At higher doses adverse signs anxiety, excitement, and combativeness. Lowering the inhaled dose will quickly reverse these adverse effects. some difficulty breathing or experience nausea and vomiting following the procedure. Drug Isoflurane (Forane) Therapeutic Class: Inhaled general anesthetic Uses: potent level of surgical anesthesia that is rapid in onset. the patient with smooth induction with a low degree of metabolism by the body. Effects Mild nausea, vomiting, and tremor are common adverse effects. The drug produces a dose-dependent respiratory depression and a reduction in blood pressure. Succinylcholine (Anectine, Quelicin) Therapeutic Class: Skeletal muscle paralytic drug; neuromuscular blocker Pharmacologic Class: Depolarizing blocker; acetylcholine receptor blocking drug succinylcholine acts on cholinergic receptor sites at neuromuscular junctions. paralysis occurs. duration of action is only a few minutes Dantrolene (Dantrium) is a drug used preoperatively or postoperatively to reduce the signs of malignant hyperthermia in susceptible patients. Alerts: can cause fetal harm Effects: Bradycardia and respiratory depression are expected adverse effects. If doses are high, the ganglia are affected, causing tachycardia, hypotension, and urinary retention. genetic defects may experience a rapid onset of extremely high fever with muscle rigidity—a serious condition known as malignant hyperthermia. Black Box Warning: Cardiac arrest has been reported resulting from hyperkalemic rhabdomyolysis most frequently in infants or children with undiagnosed skeletal muscle myopathy or Duchenne’s muscular dystrophy. This drug is reserved for use in children in cases of emergency intubation or in instances when immediate securing of the airway is necessary. Give sedation and pain meds with paralytics Ch. 20 Drugs for Degenerative Diseases of the Nervous System Three common debilitating and progressive conditions—Parkinson disease, Alzheimer disease, and multiple sclerosis—are the focus of this chapter. Alzheimer disease Progressive loss of brain function characterized by memory loss, confusion, and dementia Multiple sclerosis Demyelination of neurons in the CNS, resulting in progressive weakness, visual disturbances, mood alterations, and cognitive deficits BEta 1 interferon available as an intramuscular (IM) formulation (Avonex) or a subcutaneous formulation (Rebif) Parkinson disease Progressive loss of dopamine in the CNS, causing tremor, muscle rigidity, and abnormal movements and posture Levodopa carbidopa give more caradopa flu like symptoms (e.g., headaches, fever, chills, muscle aches), anxiety, discomfort experienced at the injection site, and hepatotoxicity Symptoms of AD are as follows: Impaired memory and judgment Confusion or disorientation Inability to recognize family or friends Aggressive behavior Depression Psychoses, including paranoia and delusions Anxiety treatment of AD is to improve function in three domains: ADLs, behavior, and cognition. Acetylcholine is naturally degraded in the synapses by the enzyme acetylcholinesterase (AChE). When AChE is inhibited, acetylcholine levels become elevated and produce a more profound effect on the receptor. Drug Benztropine (Cogentin) Therapeutic Class: Antiparkinson drug Pharmacologic Class: Centrally acting cholinergic receptor blocker Uses: relief of Parkinson-like symptoms and for the treatment of EPS brought on by antipsychotic pharmacotherapy. suppresses tremors but is not effective at relieving tardive dyskinesia. Alerts: may be taken in divided doses, two to four times a day, or the entire day’s dose may be taken at bedtime. Effects: benztropine can cause typical anticholinergic side effects, such as dry mouth, constipation, and tachycardia. Adverse general effects include sedation, drowsiness, dizziness, restlessness, irritability, nervousness, and insomnia. interacts with many drugs. Over-the-counter (OTC) cold medicines should be avoided Physostigmine 1 to 2 mg subcutaneously or IV will reverse symptoms of anticholinergic intoxication. Drug Levodopa, Carbidopa, and Entacapone (Stalevo) Therapeutic Class: Antiparkinson drug Pharmacologic Class: Dopamine precursor; dopamine-enhancing drug combination Uses: restores the neurotransmitter dopamine in extrapyramidal areas of the brain, thus relieving some Parkinson symptoms, especially tremor, bradykinesia, gait, and muscle rigidity. To increase its effect, levodopa is combined with two other drugs, carbidopa and entacapone, which prevent its enzymatic breakdown. Several months may be needed to achieve optimal therapeutic effects. Alerts: Abrupt withdrawal of the drug can result in Parkinson-like symptoms or NMS. Effects: uncontrolled and purposeless movements (such as extending the fingers and shrugging the shoulders), loss of appetite, nausea, and vomiting. Muscle twitching and spasmodic winking are early signs of toxicity. Orthostatic hypotension discontinued gradually because abrupt withdrawal can produce acute Parkinson-like symptoms. Psychosis Contraindications: Stalevo is contraindicated in patients with narrow-angle glaucoma, suspicious pigmented lesions, or a history of melanoma 2 weeks of therapy with monoamine oxidase inhibitors. Kava may worsen the symptoms of PD. ginkgo biloba have been used in traditional Chinese medicine for thousands of years. improve mental functioning and slow the dementia characteristic of Alzheimer disease. Ginkgo exhibits a relatively low incidence of side effects, with nausea, gastrointestinal (GI) upset, diarrhea, headache, and dizziness being the most common Gingko may increase the risk of bleeding, and patients taking anticoagulants Drug Donepezil (Adlarity, Aricept) Therapeutic Class: Alzheimer’s disease drug Pharmacologic Class: Cholinesterase inhibitor Uses: improves memory in cases of mild to moderate Alzheimer dementia by enhancing the effects of acetylcholine in neurons Patients should receive pharmacotherapy for at least 6 months prior to assessing maximum benefits of drug therapy. Improvement in memory may be observed as early as 1 to 4 weeks following medication. Alerts: Give medication prior to bedtime. most effective when given on a regular schedule. Effects:side effects of donepezil are vomiting and diarrhea. Less common effects are abnormal dreams, fainting, and darkened urine. CNS side effects include insomnia, syncope, depression, headache, and irritability. Musculoskeletal side effects include muscle cramps, arthritis, and bone fractures. Generalized side effects include headache, fatigue, chest pain, increased libido, hot flashes, urinary incontinence, dehydration, and blurred vision. Hepatotoxicity has not been Donepezil is contraindicated in patients with GI bleeding and jaundice. Donepezil will cause anticholinergics to be less effective Anticholinergics such as atropine may be used as an antidote for donepezil overdosage. Memantine (Namenda) is approved for treatment of moderate to severe AD. Its mechanism of action differs from that of the cholinesterase inhibitors. memantine reduces the abnormally high levels of glutamate. Too much glutamate in the brain may be responsible for brain cell death. Multiple sclerosis (MS) is a chronic, inflammatory autoimmune disorder found mostly among young adults. If treatments are started early, the frequency of disease symptoms can be slowed and permanent neurologic damage can be delayed. sign/symptoms: include fatigue, heat sensitivity, neuropathic pain, spasticity, impaired cognitive ability, disruption of balance and coordination, bowel and bladder symptoms, sexual dysfunction, dizziness, vertigo, visual impairment, and slurred speech. Interferon beta drugs are available as interferon beta-1a (Avonex, Rebif) and interferon beta-1b (Betaseron, Extavia). Interferon beta-1a products are available as an intramuscular (IM) formulation (Avonex) or a subcutaneous formulation (Rebif). Interferon beta-1b products (Betaseron, Extavia) are injected subcutaneously every other day. Effects flulike symptoms (e.g., headaches, fever, chills, muscle aches), anxiety, discomfort experienced at the injection site, and hepatotoxicity Glatiramer (Copaxone) is a synthetic protein that simulates myelin basic protein, an essential part of the nerve’s myelin coating. Copaxone is available in prefilled syringes that can be stored at room temperature for several days. As with the interferons, patients complain of self-injection side effects, such as redness, pain, swelling, itching, or a lump at the site of injection. Flushing, chest pain, weakness, infection, nausea, joint pain, anxiety, and muscle stiffness are common effects experienced with the immunomodulators. Ch 21 Drugs for Muscle Spasms and Spasticity Malignant hyperthermia is a rare, life-threatening, anesthetic-related disorder that occurs in susceptible patients following the administration of a triggering agent, such as inhaled halogenated volatile anesthetics or succinylcholine Treatment of malignant hyperthermia requires rapid identification of signs and symptoms, discontinuation of the triggering agent, institution of dantrolene therapy, and control of associated symptoms. The signs of malignant hyperthermia include muscle rigidity, rapid heart rate, high body temperature, muscle breakdown, and increased acid content Muscle spasms are involuntary contractions of a skeletal muscle or group of skeletal muscles. intermittent claudication, is a common cause of muscle cramping in the lower legs. muscle spasms may experience inflammation, edema, and pain in the affected muscle, loss of coordination, and reduced mobility. nonpharmacologic therapies include immobilization of the affected muscle, application of heat or cold, hydrotherapy, acupuncture, therapeutic ultrasound, supervised exercises, massage, physical therapy, and manipulation. herbal remedies. Examples are topical formulations of black cohosh, castor oil packs, or capsaicin, a substance derived from cayenne peppers Nonsteroidal anti-inflammatory drugs, such as aspirin, naproxen, and ibuprofen, are usually the first-line drugs for treating minor to moderate pain due to muscle overexertion. For more intense muscle spasms, centrally acting skeletal muscle relaxants Drug Cyclobenzaprine (Amrix) Therapeutic Class: Centrally acting skeletal muscle relaxant Pharmacologic Class: Catecholamine reuptake inhibitor Uses: depressing motor activity primarily in the brainstem; limited effects also occur in the spinal cord. Cyclobenzaprine increases circulating levels of norepinephrine, The drug causes muscle relaxation in cases of acute muscle spasticity, Alerts: great caution in patients older than age 65 because this population is more likely to experience confusion, hallucinations, and adverse cardiac events from the drug. Effects: drowsiness, blurred vision, dizziness, dry mouth, rash, and tachycardia. caution in patients with myocardial infarction, dysrhythmias, hypothyroidism, or severe cardiovascular disease. The intravenous (IV) administration of 1 to 3 mg of physostigmine is reported to reverse symptoms of poisoning by drugs with anticholinergic activity. Spasticity is a condition in which muscle groups remain in a continuous state of contraction mild to severe pain, exaggerated deep tendon reflexes, localized muscle spasms, scissoring (involuntary crossing of the legs), and fixed joints. Dystonia, a chronic neurologic disorder, is characterized by continuous, involuntary muscle contractions that force body parts into abnormal, occasionally painful movements or postures. It affects the muscle tone of the arms, legs, trunk, neck, eyelids, face, or vocal cords Effective treatments for spasticity are both physical therapy and medications. Dantrolene relieves spasticity by interfering with the release of calcium ions in skeletal muscle Botulinum toxin is an unusual drug because, in higher quantities, it acts as a poison. Drug Dantrolene Sodium (Dantrium, Revonto) Therapeutic Class: Skeletal muscle relaxant Pharmacologic Class: Direct-acting antispasmodic; calcium release blocker Dantrolene is especially useful for muscle spasms when they occur after spinal cord injury or stroke and in cases of CP or MS IV form (Revonto) is a preferred drug for the treatment of malignant hyperthermia. Alerts: irritating to tissue. Effects: Adverse effects include muscle weakness, drowsiness, dry mouth, dizziness, nausea, diarrhea, tachycardia, erratic blood pressure, photosensitivity, and urinary retention Black Box Warning: Hepatitis and death due to liver failure have occurred with dantrolene. The risk of hepatic injury is increased in females over 35 years of age and after 3 months of therapy. There is also a higher proportion of hepatic events with fatal outcome in older patients receiving dantrolene. Ch. 29 Shock appears pale and may claim to feel sick or weak without reporting specific complaints. Behavioral changes are often some of the earliest symptoms and may include restlessness, anxiety, confusion, depression, and apathy. Lack of sufficient blood flow to the brain may cause unconsciousness. Thirst is a common complaint. The skin may feel cold or clammy Types of Shock Anaphylactic- Acute allergic reaction -Severe reaction to an allergen such as penicillin, nuts, shellfish, or animal proteins Cardiogenic- Failure of the heart to pump sufficient blood to tissues. Fluid overload -Left heart failure, myocardial ischemia, myocardial infarction, dysrhythmias, pulmonary embolism, or myocardial or pericardial infection. Give vasopressors for vasoconstriction. Hypovolemic - Inadequate organ perfusion caused by loss of blood volume. Can get from lesix cardiac output low, low BP Fluid problem- dehydration give fluids such as isotonic: Lactated ringers, NS 0.9%, plasmalyte, albumin 5% Blood loss- low H& H give blood -Hemorrhage, burns, excessive diuresis, dehydration, or severe vomiting or diarrhea Neurogenic- Vasodilation due to overstimulation of the parasympathetic nervous system or under stimulation of the sympathetic nervous system Trauma to the spinal cord or medulla, severe emotional stress or pain, or drugs that depress the central nervous system Septic- Multiple organ dysfunction due to an infection in the blood; often a precursor to acute respiratory distress syndrome and disseminated intravascular coagulation -Widespread inflammatory response to bacterial, fungal, or parasitic infection give fluids and vasopressors such as levophed norepinephrine. For example, obvious trauma or bleeding would suggest hypovolemic shock related to blood loss. If trauma to the brain or spinal cord is evident, neurogenic shock, resulting in bradycardia and hypotension due to sudden loss of sympathetic nerve activity, may be suspected. A history of heart disease would suggest cardiogenic shock, which is caused by inadequate cardiac output due to pump failure. A recent infection may indicate septic shock, caused by the presence of bacteria or toxins in the blood and resulting in massive systemic inflammation. A history of allergy with a sudden onset of symptoms following food or drug intake may suggest anaphylactic shock, the most severe type of allergic response. The pharmacotherapy of anaphylaxis Treatment with IV Fluid replacement therapy includes blood, blood products, colloids, and crystalloids Blood products Fresh frozen plasma Immune globulins Packed red blood cells Platelets Whole blood Colloids Dextran 40 (Gentran 40, Rheomacrodex) or dextran 70 (Hyskon, Macrodex) Hetastarch (Hespan) Normal serum albumin, human (Albuminar, Plasbumin, others) Plasma protein fraction (PPFh) (Plasmanate, Plasma-Plex, Plasmatein, Protenate) Crystalloids 5% dextrose in normal saline (D5W) Hypertonic saline (3% sodium chloride) Normal saline (0.9% sodium chloride) Lactated Ringer Plasma-Lyte Crystalloids or colloids may be needed to prevent shock if the patient presents with volume depletion. Antihistamines such as diphenhydramine (Benadryl) may be administered IM or IV to prevent further release of histamine. Drug Normal Serum Albumin (Albuminar, Plasbumin, others) Therapeutic Class: Fluid replacement drug Pharmacologic Class: Blood product, colloid Uses: a protein extracted from whole blood, plasma, or placental human plasma. Albumin naturally comprises about 60% of all blood proteins. Albumin is classified as both a blood product and a colloid. Administered IV, albumin increases the osmotic pressure of the blood and causes fluid to move from the tissues to the general circulation. It is used to restore plasma volume in hypovolemic shock or to restore blood proteins concentrations of 5% and 25%. Alerts: Infuse high concentrations slowly to prevent the risk of a large, rapid fluid shift. Use a large-gauge (16- to 20-gauge) IV cannula for administration of the drug. For religious reasons, patients may refuse to accept any drug derived from human blood, including albumin Effects: Because albumin is a natural blood product, the patient may have antibodies to the donor albumin, and allergic reactions are possible Signs of allergy include fever, chills, rash, dyspnea, and possibly hypotension. Circulatory overload and edema may occur if excessive amounts of albumin are infused due to fluid being moved into the vascular system. severe anemia or cardiac failure Vasoconstrictors used to treat shock include dopamine, norepinephrine (Levophed), phenylephrine (Neo-­Synephrine), and epinephrine. Because dopamine also affects the strength of myocardial contraction, it is considered both a vasoconstrictor and an inotropic drug Epinephrine is usually associated with the treatment of anaphylaxis Inotropic drugs, also called cardiotonic drugs, have the potential to reverse the cardiac symptoms of shock by increasing the strength of myocardial contraction. Dobutamine is a selective Beta 1-adrenergic drug that has value in the short-term treatment of certain types of shock due to its ability to cause the heart to beat more forcefully. Dobutamine is especially beneficial when the primary cause of shock is related to heart failure rather than to hypovolemia. Dopamine activates both beta- and alpha-adrenergic receptors. It is primarily used in shock conditions to increase blood pressure by causing peripheral vasoconstriction ( Alpha 1 activation) and increasing the force of myocardial contraction ( Beta 1 activation). Dopamine has the potential to cause dysrhythmias Drug Norepinephrine (Levophed) Therapeutic Class: Drug for shock Pharmacologic Class: Nonselective adrenergic agonist: vasoconstrictor Uses: Norepinephrine is a sympathomimetic that acts directly on alpha-adrenergic receptors in vascular smooth muscle to immediately raise blood pressure. a positive inotropic response that may increase cardiac output. Its primary indications are acute shock and cardiac arrest. Norepinephrine is a preferred vasoconstrictor for septic shock because it has been shown to decrease mortality. Alerts: patency of the IV and monitor the flow rate continuously. If extravasation occurs, administer phentolamine etal harm in pregnant Effects: patient’s blood pressure is required to prevent the development of hypertension (HTN). When first administered, reflex bradycardia may be experienced. It also has the ability to produce various types of dysrhythmias, Blurred vision and photophobia are signs of overdose. Black Box Warning: Extravasation may cause serious skin and soft tissue injury; the affected area should be infiltrated immediately with 5–10 mg of phentolamine, an adrenergic blocker. Contradictions: not be administered to patients who are experiencing hypotension due to blood volume deficits overdose: Discontinuing the infusion usually results in a rapid reversal of adverse effects, such as HTN. Drug Dopamine Therapeutic Class: Drug for shock Pharmacologic Class: Nonselective adrenergic agonist; inotropic drug Uses: its mechanism of action is dependent on the dose. At low doses, the drug selectively stimulates dopaminergic receptors, especially in the kidneys, leading to vasodilation and an increased blood flow through the kidneys. treating hypovolemic and cardiogenic shock. At higher doses, dopamine stimulates Beta 1 -adrenergic receptors, causing the heart to beat more forcefully and increasing cardiac output. vasoconstriction and raising blood pressure. Alerts: Ensure the patency of the IV prior to beginning the infusion and monitor infusions continuously. administer phentolamine to the area of infiltration as soon as possible. causes fetal harm in pregnant Effects: continuously monitored for signs of dysrhythmias and HTN. Adverse effects are normally self-limiting because of the drug’s short half-life. can cause severe, irreversible skin and soft tissue damage if the drug infiltrates. Black Box Warning: Following extravasation, the affected area should be infiltrated immediately with 5–10 mg of phentolamine, an adrenergic blocker. Drug Epinephrine (Adrenalin) Therapeutic Class: Drug for anaphylaxis and shock Pharmacologic Class: Nonselective adrenergic agonist; vasoconstrictor Uses: Subcutaneous or IV epinephrine is a preferred drug for anaphylaxis because it can reverse many of the distressing symptoms within minutes. blood pressure rises due to stimulation of Alpha 1 receptors. Activation of Beta 2 receptors in the bronchi open the airways and relieves the patient’s shortness of breath. Effects: The most common adverse effects of epinephrine are nervousness, tremors, palpitations, tachycardia, dizziness, headache, and stinging or burning at the site of application. HTN and dysrhythmias may occur rapidly; therefore, the patient should be monitored carefully following injection.