Unit 5 CNS and PNS Drugs PDF

CENTRAL NERVOUS SYSTEM & PERIPHERAL NERVOUS SYSTEM DRUGS PROF. JERICHO E. CRUZ The Brain: Numerous drugs can stimulate the CNS. 1. Stimulants 2. Depressants 3. Anti-seizure Drugs 4. Drugs for Parkinsonism and Alzheimer’s Disease 5. Drugs for Neuromuscular...

CENTRAL NERVOUS SYSTEM & PERIPHERAL NERVOUS SYSTEM DRUGS PROF. JERICHO E. CRUZ The Brain: Numerous drugs can stimulate the CNS. 1. Stimulants 2. Depressants 3. Anti-seizure Drugs 4. Drugs for Parkinsonism and Alzheimer’s Disease 5. Drugs for Neuromuscular Disorders and Muscle Spasm  AMPHETAMINE- ANALEPTICS LIKE DRUGS ANOREXIANTS AMPHETAMINE A. CNS Stimulants Are medicines that stimulate the brain, speeding up both mental and physical processes. They increase energy, improve attention and alertness, and elevate blood pressure, heart rate and respiratory rate. They decrease the need for sleep, reduce appetite, improve confidence and concentration, and lessen inhibitions.  1. Amphetamine Stimulates the release of neurotransmitters – norepinephrine and dopamine INDICATIONS: narcolepsy, ADHD Sample Drug Brand: Adderall CAN DEVELOP DEPENDENCE SHORT-TERM (12 WEEKS) AVOID ABRUPT WITHDRAWAL HALF LIFE: 9-13 HRS S/E and A/R: (T.I.R.E.D P.I.A) TACHYCARDIA, INSOMNIA, RESTLESSNESS, ELEVATED BP, DRY MOUTH PALPITATIONS, IMPOTENCE, ANOREXIA Difference between drug Tolerance, Dependence and Addiction: TOLERANCE – Occurs when someone abuses a drug for a long period of time (becoming used with it, hence, less effective)… DEPENDENCE – When someone abuses a high dose of addictive substance, it will develop dependence. They feel they cannot function normally if they cannot use this drug. (many negative effects). ADDICTION – Drugs that affect someone’s mind. Inability to control the use of drugs or alcohol.  2. Amphetamine-like Drug ACTION: to increase child’s attention span, cognitive performance and to decrease impulsiveness, hyperactivity and restlessness E.g. Methylphenidate (Ritalin) – ADHD – INSOMNIA! DON’T GIVE 6 HRS BEFORE BEDTIME. Pemoline (Cylert) - narcolepsy Modafinil (Provigil) – newest ADHD – Attention Deficit Hyperactivity Disorder  NR Responsibilities in giving ALD RITALIN and PEMOLINE should be given 30 to 45 minutes before meals (breakfast and lunch) Never give within 6 hours before sleep Instruct the patient to avoid driving Instruct the nursing mother to avoid taking CNS stimulants Explain to client that long-term use may lead to drug abuse. DRY MOUTH – SUGARLESS GUMS WOF: TOURETTE SYNDROME (TICS) – INVOLUNTARY TWITCHING – EYES, MOUTH. Difference between Adderall and Ritalin 3. Anorexiants Appetite Suppressants S/E: (P.E.N. I.R.I) PALPITATIONS IRRITABILITY ELEVATED BPRESTLESSNESS NERVOUSNESS INSOMNIA AVOID: < 12 Y/O; SELF MEDICATION 4. Analeptics Stimulate respiration (Respiratory Stimulants) Sample Drug Class: 1. “METHYLXANTHINES” 1.1. caffeine (Caffeine citrate) 1.2. Theophylline (Bronchodilator) – NEWBORN – USED: RESPIRATORY DISTRESS S/E: nervousness, restlessness, tremors, twitching, palpitations and insomnia, diuresis, GI irritation, tinnitus Methylxanthine Action  2. Doxapram (Dopram) Treats: Respiratory Depression ---- Drug Over dose!!! Also: Anesthesia OD and COPD S/E: HPN, tachycardia, trembling, and convulsions 1.Barbiturates 2.Benzodiazepine 3.Non-Benzodiazepine 4.Melatonin Agonists 5.Chloral Hydrate 6.Anesthesia B. CNS Depressants Central nervous system depressants are medications or substances that slow brain activity. As a result, leads to side effects such as drowsiness, relaxation, and decreased inhibition. These drugs cause a “SEDATIVE-HYPNOTIC” effect once used to patients. These drugs operate by affecting the neurotransmitter gamma- aminobutyric acid (GABA), which leads to side effects such as drowsiness, relaxation, and decreased inhibition. Question: What is Sedative Hypnotics? “Sedative-Hypnotics” SEDATION – diminish physical and mental response at a lower dosages of certain CNS depressants but does not affect consciousness Hypnotic – natural sleep  1: Barbiturates (Arbital) SHORT-ACTING - Secobarbital INTERMEDIATE- (Seconal) ACTING - Pentobarbital - Amobarbital (Amytal) (Nembutal) LONG ACTING - Aprobarbital (Alurate) - Butabarbital (Butisol) - induce sleep for Phenobarbital and those difficulty falling Mephobarbital asleep - sleep sustainers for - used to control seizures in maintaining long period of ULTRASHORT- epilepsy sleep ACTING -causes drowsiness / - Thiopental Na hangover (Pentothal) - general anesthetics  NR to those who take Barbiturates: Barbiturates – short term use only! (2 weeks or less) abrupt withdrawal Raise bedside rails. Check skin for rashes. Administer IV pentobarbital at a rate of less than 50mg/min. Do not mix pentobarbital w/ other medications. Deep IM in gluteus Medius. Teach client to use non pharma ways to induce sleep. Instruct to avoid alcohol and antidepressant, antipsychotic and narcotics – morphine sulfate!. Wof: respiratory depression / cns depression; hepatotoxicity esp. when combined with acetaminophen! 2. Benzodiazepines (Pam/Lam) ACTION: increase the action of inhibitory neurotransmitter GABA > neuron excitability is reduced! FLURAZEPAM (DALMANE) – first - used to treat insomnia Triazolam (Halcion) – A/R: loss of memory (anterograde amnesia / memory impairment); should not be taken longer than 7-10 days Temazepam (Restoril), Estazolam (ProSom), Quazepam (Doral) Diazepam (Valium), Lorazepam (Ativan) NR to those who take Benzodiazepine: Avoid alcohol, antidepressants, antipsychotics Urinate before taking the drug – causes urinary retention! No OTC drugs Caution in driving Antidote: Flumazenil (Benzodiazepine Antagonist) 3. Non-Benzodiazepine Newest drug class of hypnotics 4. Melatonin Agonists 5. CHLORAL HYDRATE Induces sleep and decrease nocturnal awakenings Used in the short-term treatment of insomnia (to help you fall asleep and stay asleep for a proper rest) and to relieve anxiety and induce sleep before surgery.  6. Anesthesia Are used to prevent pain during surgery and other procedures. These medicines are called anesthetics. They may be given by injection, inhalation, topical lotion, spray, eye drops, or skin patch. They cause you to have a loss of feeling or awareness. Nitrous Oxide (N2O) – Also Known as laughing Gas, is the first used anesthesia especially for dental surgery. Types of Anesthesia: Local anesthesia numbs a small part of the body. It might be used on a tooth that needs to be pulled or on a small area around a wound that needs stitches. You are awake and alert during local anesthesia. Regional anesthesia is used for larger areas of the body such as an arm, a leg, or everything below the waist. You may be awake during the procedure, or you may be given sedation. Regional anesthesia may be used during childbirth, a Cesarean delivery (C-section), or minor surgeries. General anesthesia affects the whole body. It makes you unconscious and unable to move. It is used during major surgeries, such as heart surgery, brain surgery, back surgery, and organ transplants.  Stages of General Anesthesia 1.Analgesia / Induction -decreased pain awareness, sometimes with amnesia, impaired consciousness but not lost. 2.Excitement or delirium – excitation, amnesia, enhance reflexes, uncontrolled movement, irregular respiration, urinary incontinence  3. Surgical stage – Unconscious, no pain reflex, regular respiration, maintained BP Plane 1: light anethesia Plane 2: loss of blink reflex, regular respiration. Surgical procedures can be performed Plane 3 – Deep anesthesia: Shallow breathing; assisted by ventilator! Plane 4 – Diaphragmatic breathing only! VENTILATOR IS REQUIRED! CAUSES CARDIOVASCULAR IMPAIRMENT! 4. Medullary paralysis – TOO DEEP > OVERDOSAGE > CIRCULATORY/RESPI COLLAPSE > DEATH!  Routes: Inhalation Anesthesia Gas or volatile liquids administered as gas A/R: respiratory depression, hypotension, dysrhythmias, hepatic dysfunction Halothane, Methoxyflurane, Enflurane, Isoflurane, Desflurane, Sevoflurane Nitrous oxide, Cyclopropane WOF: MALIGNANT HYPERTHERMIA! MGT: DANTROLENE (Treats muscle spasm)  Routes: Intravenous Anesthesia As general anesthesia Thiopental Na (Penthotal) Methohexital Na (Brevital) Ketamine HCl (Ketalar) Midazolam Profopol A/R: respiratory and cardiovascular effects/depression WOF: INFECTIONS – PROPOFOL SUPPORTS MICROBIAL GROWTH  Routes: Topical Anesthesia Mucous membrane; broken or unbroken skin surface, burns Solution, liquid spray, ointment, cream, and gel LOCAL ANESTHETICS – LIDOCAINE! – DENTAL PROCEDURES, SUTURES,DIAGNOSTICS – LUMBAR PUNCTURE, THORACENTESIS  Routes: Spinal Anesthesia Local anesthesia injected into subarachnoid space 3rd to 4th lumbar space – children! 1st LS (adult) S/E and A/R: respi distress (spread too high in spinal column > respiratory muscle), headache (decrease in CSF pressure), hypotension (sympathetic blockade) Nerve block: spinal block (subarachnoid space); epidural block (dura mater); caudal block (near the sacrum); saddle block (lower end of spinal column) Nurse role: Complete the pre-operative orders Including the pre-medications AKA: ANTI-CONVULSANTS What is a Seizure? 2 Kinds of Seizures  C. ANTI SEIZURE DRUGS Also called : “ANTI-EPILEPTICS” "ANTI-CONVULSANTS” ACTION: to suppress the abnormal electrical impulses from the seizure focus to other cortical areas, preventing seizures Common Anti-Convulsant Drugs HYDANTOIN BARBITURATES SUCCINIMIDE OXAZOLIDONES/ OXAZOLIDINEDIONE BENZODIAZIPINE  Hydantoin - Slows the synaptic transmission by blocking Sodium channels from recovering from the inactivated state, and inhibits neurons from firing. 1.PHENYTOIN (Dilantin) SIDE EFFECTS/A.R: First anticonvulsant gingival hyperplasia 1938 depression thrombocytopenia TERATOGENIC leukopenia Therapeutic range = 10- hyperglycemia NV, constipation 20 mcg/ml IV, PO, no IM (tissue damage)  NR to HYDANTOIN PHENYTOIN Shake the suspension well Instruct client not to drive No alcohol and antidepressants Medic alert ID Not to abruptly stop the drug therapy No OTC Take this drug with food or milk Instruct the client that urine will become reddish pink/reddish brown Use soft bristles Risk for infection Barbiturates – It enhances the action of GABA, which is an inhibitory neurotransmitter, and inhibits initiation of discharge that would start the seizure. PHENOBARBITAL Partial and status epilepticus Teratogenic Gradual discontinuance Succinimide - act on calcium 'T' channels to block voltage-dependent calcium conductance in thalamic neurons. Used for absence or petit-mal seizures S/E: blank stare – children! ETHOSUXINIMIDE = succinimide of choice Methsuximide and Phensuximide Benzodiazipine - They mainly work by affecting the gamma amino-butyric acid (GABA) neurotransmitters in the brain. CLONAZEPAM -petit-mal CLORAZEPATE DIPOTASSIUM - Partial seizure -acute status epilepticus – DIAZEPAM severe seizure! - IV  Drugs for : PARKINSON’S DISEASE & ALZHEIMER’S DISEASE How does it occur?  A. Dopaminergic 1. LEVODOPA – Most commonly used drug. This is the precursor of Dopamine. - Converted to dopamine; most effective in diminishing the symptoms of Parkinson's disease - S/E: nausea, vomiting, dyskinesia, hypotension, psychosis, cardiac dysrhythmias 2. CARBIDOPA – Alternative drug combined with Levodopa; It works by preventing levodopa from being broken down before it reaches the brain. NR to patients taking Levodopa/Carbidopa: Monitor VS especially BP ECG Assess for signs and symptoms of parkinsonism Low protein foods Overdose: Psychotic episodes happen!!!  B. Dopamine Agonists ACTION: Stimulate the dopamine receptors AMANTADINE HCL (SYMMETREL) – antiviral that acts on the dopamine receptors S/E: orthostatic hypo, confusion, urinary retention, constipation BROMOCRIPTINE (PARLODEL) – acts directly on CNS, CVS, and GIT S/E: orthostatic hypo, palpitations, chest pain, edema, nightmares, delusions, confusion NR to patients taking Dopamine Agonists: Report any signs of skin lesions, seizures, or depression Assess for orthostatic hypotension Avoid alcohol Monitor VS especially BP and HR Not to abruptly stop the drug  C. Anti-Cholinergic ACTION: Inhibit the release of acetylcholine 1. Benztropine (Cogentin) This helps decrease muscle stiffness, sweating, and the production of saliva, and helps improve walking ability in people with Parkinson's disease. 2. Biperiden (Akineton) competitive antagonism of acetylcholine at cholinergic receptors in the corpus striatum, which then restores the balance.  3. Trihexyphenidyl (Artane) blocking a certain natural substance (acetylcholine). This helps decrease muscle stiffness, sweating, and the production of saliva, and helps improve walking ability in people with Parkinson's disease.Anticholinergics can stop severe muscle spasms of the back, neck, and eyes that are sometimes caused by psychiatric drugs. 4. Diphenhydramine HCl (Benadryl) In patients with Parkinson's disease, diphenhydramine may be used to decrease stiffness and tremors due to its anticholinergic effect.  D. Mono-Amine Oxidase-B Inhibitor (MAO-B Inhibitor) ACTION: Stops MAO enzyme so that more dopamine becomes available to treat your symptoms. Furthermore, prolongs Levodopa action. Mono Amine Oxidase – Removes excess Dopamine in the brain!!!! BUT……………… MAO-B INHIBITOR inhibits MAO-B As a result…. More Dopamine inside the brain!!!! MAO B inhibitor drugs commonly used for Parkinson's disease include: 1. Selegiline (brand names: Eldepryl, Zelapar): It is used as an adjunct to levodopa-carbidopa medications to enhance their effectiveness and reduce motor fluctuations. 2. Rasagiline (brand name: Azilect): It is also used as an adjunct to levodopa-carbidopa medications to improve motor symptoms and reduce motor fluctuations.  3. Safinamide (brand name: Xadago): It is used as an add-on therapy to levodopa-carbidopa medications to improve motor symptoms and prevent "off" episodes. NOTE: By inhibiting MAO-B, these drugs increase dopamine levels and help alleviate Parkinson's symptoms.  Alzheimer’s Disease: Most common type of dementia A progressive disease beginning with mild memory loss and possibly leading to loss of the ability to carry on a conversation and respond to the environment. It later affects areas in the cerebral cortex responsible for language, reasoning, and social behavior. Drugs commonly used for Alzheimer's disease: Relieves symptoms of: Memory Loss Confusion Difficulty in thinking and reasoning ACTION: They work by improving the communication between nerve cells in the brain or by regulating the levels of certain chemicals involved in Alzheimer's disease Note: Only slows down the progression of AD but not to cure!!!  1. Cholinesterase inhibitors: - Donepezil (Aricept) - Rivastigmine (Exelon) - Galantamine (Razadyne) 2. N-methyl-D-aspartate (NMDA) receptor antagonist: - Memantine (Namenda) Drugs For: NEUROMUSCULAR DISORDER & MUSCLE SPASM  Neuromuscular disorders; Affect the nerves that control certain muscles in your body. These muscles are called your voluntary muscles — they’re the muscles you can choose to move such as the ones in your arms, legs, or face. Disorders that affect voluntary muscles can be genetically inherited (passed down from your parents) or may develop over time as a complication of certain health conditions such as an autoimmune disorder.  A. Myasthenia Gravis Autoimmune disease Destructs Acetylcholine due to The presence of Acetylcholinesterase Resulting to weakness of muscles DRUGS FOR : 1. Acetylcholinesterase Inhibitors/ Cholinesterase Inhibitors Neostigmine (Prostigmin) – 1st drug Pyridostigmine bromide (Mestinon) - increases muscle strength Ambenonium chloride (Mytelase) Edrophonium chloride (Tensilon) - used to distinguish myasthenia crisis from cholinergic crisis S/E & A/R: GI disturbances, increased salivation, tearing, miosis, HPN NR to patients taking Mestinon: Administer IV undiluted Atropine sulfate as antidote for cholinergic crisis Take the drug before meals Assess for the effectiveness of the drug therapy Avoid: Baclofen (Lioresal) – paralysis! B. MULTIPLE SCLEROSIS  Commonly Used drug for MS: Interferon beta-1a - Reducing inflammation and slowing down the progression of the disease. (Immunosuppressant) Corticosteroids – For inflammation Monoclonal Antibody – To reduce frequent attacks and exacerbations. 1. Alemtuzumab 2. Natalizumab MUSCLE RELAXANTS: Nursing Consideration: Dizziness is expected upon changing position No alcohol while taking the medication Do not abruptly stop! (Rebound effect) Drowsiness is also excepted Centrally Acting Skeletal Muscle Relaxants: Spasmolytics Suppress hyperactive reflexes Decrease pain and increase range of motion Have a sedative effect Drugs for Skeletal Muscle Spasticity: Dantrolene - It relieves the spasms, cramping, and tightness of muscles caused by certain medical problems such as multiple sclerosis (MS), cerebral palsy, stroke, or injury to the spine. Baclofen - Is a muscle relaxant. It's used to relieve muscle spasms, cramping or tightness caused by conditions such as: cerebral palsy. Diazepam (Valium) - relaxes muscle spasms that are causing pain or stiffness. Drugs for Skeletal Muscle Spasm: Carisoprodol (Soma) - Interrupts neuronal communication within the reticular formation and spinal cord, resulting in sedation and alteration in pain perception. Methocarbamol (Robaxin) - Works by calming overactive nerves in your body, which helps your muscles relax. Orphenadrine citrate (Norflex)- binds and inhibits both histamine H1 receptors and NMDA receptors. It restores the motor disturbances induced by neuroleptics, in particular the hyperkinesia. NOTE: No need to report sleepiness and sedation because its normal… NR to patients taking Muscle Relaxants: Monitor serum liver enzyme levels Do not abruptly stop the medication Not to drive or operate dangerous machinery Avoid alcohol and CNS depressants C/I with pregnant women ; nursing mothers Take with food