Toxic Effects of Drugs PDF

Summary

This document discusses the different toxic effects of drugs, including primary actions, secondary actions, and hypersensitivity. It details the various types of adverse drug reactions, and how they may affect different body systems. It also covers the topic of drug allergies.

Full Transcript

TOXIC EFFECTS OF DRUGS However adverse effects are almost All drugs are Potentially dangerous. inevitable. Drugs are chemicals, and the human Ex: antihistamine are very effective in body operates by a vast series of drying up secretions and he...

TOXIC EFFECTS OF DRUGS However adverse effects are almost All drugs are Potentially dangerous. inevitable. Drugs are chemicals, and the human Ex: antihistamine are very effective in body operates by a vast series of drying up secretions and helping chemical reactions. breathing, but they also cause Consequently, many effects can be seen drowsiness. when just one chemical factor is altered. 3. HYPERSENSITIVTY Some patients are excessively ADVERSE EFFECT responsive to either the primary or Are undesired effects that may be secondary effects of a drug. unpleasant or even dangerous. This is known hypersensitivity, and it They can occur for many reasons. may result from a pathological or Including the following: underlying condition. The drug may have other effects on the Ex: drugs are excreted in kidneys. body besides the therapeutic effect. Patient with kidney problems may not be The patient may be sensitive to the drug able to excrete the drug and may being given. accumulate drug in the body causing The drugs action on the body may toxic effects. cause other responses that are The patient will exhibit exaggerated undesirable or unpleasant. adverse effects from a standard dose of The patient may be taking too much or the medication because of the too little of the drug, leading to adverse accumulation of the drug. effects. Each persons has slightly different receptors and cellular responses. TYPES OF ADVERSE EFFECTS: Frequently elder people will react to narcotics with increased stimulation and 1. PRIMARY ACTIONS hyperactivity, not with sedation that is Most common occurrences in drug expected. therapy is the development of adverse Hypersensitivity also can occur if a effects form simple overdose. patient has an underlying condition that The patient suffers from the effects that makes the drug's effects especially are merely an extension of the desired unpleasant or dangerous. effects Ex: a patient with an enlarged prostate Ex: anticoagulant may act so who takes an anticholinergic drug may effectively that the patient experiences develop urinary retention or even bladder excessive and spontaneous bleeding. paralysis when the drug's effect block the 2. SECONDARY ACTIONS/ urinary sphincter. SECONDARY EFFECT Drugs can produce a wide variety of effects in addition to the desired DRUG ALLERGY pharmacological effect. Occurs when the body forms antibodies Sometimes the drug dose can be to a particular drug, causing an immune adjusted so that the desired effect is response when the person is reexposed achieved without producing undesired to the drug. secondary reactions. A patient cannot be allergic to a drug that has never been taken, although patients can have cross-allergies to drugs >>> Assessment:Itch rashes, high fever, within the same drug class as one swollen lymph nodes, swollen &painful formerly taken. joints, edema of the face and limbs. Ex: a patient stated that she was allergic to the diuretic furosemide (Lasix). DELAYED ALLERGIC REACTIONS On further questioning the nurse This reaction occurs several hours after discovered that the patient considered exposure and involves antibodies that are herself to be "allergic" to the drug effect, bound to specific white blood cells. but one that the patient thought was a >>> Assessment:Rash, hives, swollen reaction to the drug. joints (similar to the reaction to poison Drug allergies classification: ivy) anaphylactic reactions, cytotoxic reactions, serum sickness, and delayed DRUG-INDUCED TISSUE & ORGAN reactions. DAMAGED Drugs can act directly or indirectly to ANAPHYLACTIC REACTION cause many types of adverse effects in This allergy involves an antibody that various tissues, structures, and organs. reacts with specific sites in the body to the possibility that these effects can cause the release of chemicals, including occur also accounts for the histamine, that produced immediate contraindications for the use of some reactions that can lead to respiratory drugs in patients with a particular history distress and even respiratory arrest. or underlying pathology. >>> Assessment: Hives, rash, difficulty The specific contraindications and breathing, increased BP, diaphoresis, cautions for the administration of a given "panic" feeling, increased heart rate, drug are noted with each drug type respiratory arrest. discussed in this book and in the individual monographs found in various CYTOTOXIC REACTIONS drug guides. This allergy involves antibodies that circulate in the blood and attack antigens DERMATOLOGIC REACTIONS (the drug) on the cell sites, causing death Are adverse reactions involving the skin. of that cell. This reaction is not immediate These can range from simple rash to but may be seen over a few days. potentially fatal exfoliative dermatitis. >>> Assessment: CBC showing damage Many adverse reactions involve the skin to blood-forming cells HCT, WBC, & PLT; because many drugs can deposit there or liver functions test: elevated liver cause direct irritation to the tissue. enzymes; decreased renal function. RASHES, HIVES SERUM SICKNESS REACTION Many drugs are known to cause skin Involves antibodies that circulate in the reactions. blood and cause damage to various Meprobamate, a drug used to treat tissues by depositing in blood vessels. anxiety, is associated with an itchy, red This reaction may occur up to 1 week or rash and in some patients has caused a more after exposure to the drug. serious and potentially fatal skin reaction, Steven- Johnson syndrome. Although many patients will report that >>>ASSESSMENT: they are allergic to a drug because they Symptoms can include swollen gums, develop a skin rash when taking the drug, inflamed gums (gingivitis), and swollen it is important to determine whether a and red tongue (glossitis). Other rash is a commonly associated adverse symptoms include difficulty swallowing, effect of the drug. bad breaths, and pain in the mouth and >>> ASSESSMENT: throat. Hives, rashes, and other dermatological >>>INTERVENTIONS: lesions may be seen. Sever reactions Provide frequent mouth care with a may include exfoliative dermatitis, which nonirritating solution. is characterized by rash and scaling, Offer nutrition evaluation and fever, enlarged lymph nodes, enlarged development of a tolerated diet, which liver, and the potentially fatal erythema usually involves frequent, small meals. multiforme exudativum (Steven-Johnson syndrome), which is characterized by SUPERINFECTIONS dark red papules appearing on the One of the body's protective mechanism extremities with no pain or itching, often is provided by the wide variety of bacteria in rings or disk-shaped patches. that live within or on the surface of the >>> INTERVENTIONS: body and in the Gl tract. In mild cases, provide frequent skin This bacterial growth is called the care; instruct the patient to avoid rubbing, normal flora. wearing tight or rough clothing, and using Several kinds of drugs (especially harsh soaps or perfumed lotions; and antibiotics) destroy the normal flora, administer antihistamine. as appropriate. leading to the development of In severe cases, discontinue the drug superinfections, or infections caused by and notify the prescriber and/or primary organisms that are usually controlled by caregiver. the normal flora. >>>ASSESSMENT: STOMATITIS Symptoms can include fever, diarrhea, Inflammation of the mucous black or hairy tongue, inflamed and membranes, can occur because of a swollen tongue (glossitis), mucous direct toxic reaction to the drug or membrane lesions, and vaginal discharge because the drug deposits in the end with or without itching. capillaries in the mucous membranes, >>>INTERVENTIONS: leading to inflammation. Provide measures (frequent mouth Many drugs are known to cause care, skin care, access to bathroom stomatitis. facilities, small & frequent meals.) Antineoplastic drugs commonly cause Administer antifungal therapy as these problems because they are toxic to appropriate. rapidly turning-over cells such as those In severe cases, discontinue the drug found in the Gl tract. responsible for the superinfection. Patients receiving antineoplastic drugs are usually given instructions for proper BLOOD DYSCRASIA mouth care when the drugs are started. Is bone marrow suppression caused by drug effects. This occurs when drugs that can cause Most drugs are metabolized in the liver, cell death are used. so any metabolites that are irritating or Bone marrow cells multiply rapidly; they toxic will also affect liver integrity. are said to be rapidly turning over. >>>ASSESSMENT: Because they go through cell division Fever, malaise, nausea, vomiting, and multiply so often, they are highly jaundice, change in color of urine or susceptible to any agent that disrupts cell stools, abdominal pain or colic, elevated function. liver enzymes, alterations in bilirubin >>>ASSESSMENT: levels, and changes in clotting factors. Fever, chills, sore throat, weakness, >>>INTERVENTIONS: back pain, dark urine, decreased Discontinue the drug and notify the hematocrit (anemia), low platelet count prescriber and/or primary caregiver. (leukoplenia), and a reduction of all Offer supportive measures such as cellular elements of the complete blood small, frequents meals, skin care, a cool count (pancytopenia). environment, and rest periods. >>>INTERVENTIONS: Monitor blood counts. Provide safety measures (rest, RENAL INJURY protection from exposure to infections, The glomerulus in the kidney has a protection from injury, avoidance of very small capillary network that filters the activities that might result in injury or blood into the renal tubule. bleeding). Some drug molecules are just the right In severe cases, discontinue the drug or size to get plugged into the capillary stop administration until the bone marrow network, causing acute inflammation and recovers to a safe level. several renal problem. Some drugs excreted from the kidney TOXICITY unchanged; they have the potential to Introducing chemicals into the body can directly irritate the renal tubule and alter sometimes affect the body in a very normal absorption and secretion noxious or toxic way. processes. These effects are not acceptable Gentamicin, a potent antibiotic, is adverse effects but are potentially serious frequently associated with renal toxicity. reactions to a drug. When a drug is known to have toxic effects the benefit of ASSESSMENT the drug to the patient must be weighed Elevated blood urea nitrogen, elevated against the possibility of toxic effects creatinine concentration, decreased which may cause the patient harm. hematocrit, electrolyte imbalances, fatigue, malaise, edema, irritability, and LIVER INJURY skin rash may seen. Oral drugs are absorbed and passed directly into the liver in the first-pass INTERVENTIONS effect. - Notify the prescriber and/or primary This exposes liver cells to the full impact caregiver and discontinue the drugs as of the drug before it is broken down for needed circulation throughout the body. - Offer supportive measures- ex, positioning, diet and fluid restrictions, skin care, electrolyte therapy, rest periods, or lips; confusion; and rapid and and a controlled environment. shallow respirations. - In severe cases, be aware that dialysis - In severe cases, seizures and/or coma may be required for survival. may occur. POISONING INTERVENTIONS: - Occurs when an overdose of a drug - Restore glucose damages multiple body systems, - Provide supportive measure (e.g., skin leading to the potential for fatal care). reactions. - Institute safety measures to prevent - Assessment parameters vary with the injury or falls. particular drug. - Monitor blood glucose levels. - Treatment of drug poisoning also - Offer reassurance. varies, depending on the drug. - Throughout this book, specific HYPERGLYCEMIA antidotes or treatments for poisoning - Some drugs stimulate the breakdown are identified, if known. of glycogen or alter metabolism in such ALTERATIONS IN GLUCOSE way as to cause high serum glucose METABOLISM levels, or hyperglycemia. - All cells need glucose for energy; the - Ephedrine, a drug used as cells of the central nervous system are bronchodilator and antiasthma drug especially dependent on constant and to relieve nasal congestion. glucose levels to function properly. >>> ASSESSMENT - The control of glucose in the body is an - Fatigue, increased urine (polyuria), integrated process that involves a increased thirst (polydipsia), deep series of hormones and enzymes that respirations, restlessness, increased use the liver as the place for glucose hunger (polyphagia), nausea, hot or storage or release. flushed skin, and fruity odor to breathe may be observed. AHYPOGLYCEMIA INTERVENTIONS - Some drugs affect metabolism and the - Administer insulin therapy use of glucose, causing a low serum - Provide support to help the patient deal blood glucose concentration, or with signs and symptoms. hypoglycemia. - Glipizide and Glyburide are antidiabetic agents that have desired action of ELECTROLYTE IMBALANCES lowering the blood glucose level but - Because they are chemicals acting in can lower blood glucose too far, a body that works by chemical causing hypoglycemia. reactions, drugs can have an effect on ASSESSMENT: various electrolyte levels in the body. - Fatigue; drowsiness; hunger; anxiety; - The electrolyte that can cause the headache; cold, clammy skin; shaking most serious effects when it is altered, and lack of coordination; increased even a little, is potassium. heart rate; increased Bp; numbness and tingling of the mouth, tongue, and/ HYPOKALEMIA INTERVENTION: - Some drugs affecting the kidney can - Use of sodium polystyrene sulfonate cause low serum potassium levels - Offer supportive measures to cope with (hypokalemia) by altering the renal discomfort exchange system. - Institute safety measures to prevent Ex: loop diuretics function by causing the injury/fall. loss of potassium, as well as of sodium - Monitor for cardiac irregularities and water. - Potassium is essential for the normal SENSSORY EFFECT functioning of nerves and muscles. - Drugs can affect the special senses, >>>>ASSESSMENT including the eyes and ears. Lower serum potassium concentration - Alterations in seeing and hearing can (3.5mEq/L), weakness, numbness & pose safety problems for patients. tingling in the extremities, muscles cramps, nausea, vomiting, diarrhea, OCULAR DAMAGE decreased bowel sounds, irregular - The blood vessels in the retina are pulse, weak pulse, orthostatic very tiny and are called "end arteries" hypotension, and disorientation. that is, they stop and do not In severe cases, paralytic ileus may interconnect with other arteries feeding occur. the same cells. - Some drugs are deposited into these INTERVENTIONS tiny arteries, causing in ammation and - Replace serum potassium and monitor tissue damage. serum level. - Chloroquine (Aralen), a drug that can - Provide support therapy cause retinal damage & even - Cardiac monitoring blindness. >>>>>>>ASSESSMENT HYPERKALEMIA - Blurring of vision, color vision - Some drugs that affect the kidney, changes, corneal damage, and such as high potassium retention and a blindness may be noted. resultant increase in serum potassium levels (hyperkalemia). INTERVENTIONS - Other drugs that cause cell death or - Monitor patient's vision when receiving injury, such as many antineoplastic known oculotoxic drugs. agents, also can cause the cells to - Provide supportive measures. relase potassium, leading to - monitor lighting and exposure to hyperkalemia. sunlight. >>>ASSESEEMENT: - High serum potassium level more than AUDITORY DAMAGE 5.0mEq/L, weakness, muscle cramps, - Tiny vessels and nerves in the eight diarrhea, numbness and tingling, slow cranial nerve are easily irritated and heart rate, low blood pressure, damaged by certain drugs. decreased urine output, and dif culty - The macrolide antibiotics, breathing. streptomycin, can cause severe auditory damage. fl fi - Aspirin, is linked to auditory ringing and ATROPINE-LIKE EFFECTS eight cranial nerve effects. - Some drugs blocks the effects of the parasympathetic nervous system by >>> ASSESSMENT directly or indirectly blocking - Dizziness, tinnitus, loss of balance, cholinergic receptors. and loss of hearing. - Atropine, is the prototype - >> ASSESSEMENT anticholinergic drug - Monitor patient's perceptual losses or - Many cold remedies and antihistamine changes. also cause anticholinergic effects. - Provide protective measures. - Provide supportive measures to cope >>>>>ASSESSMENT with the drug effects. - Dry mouth, altered taste perception, dysphagia, heartburn, constipation,, NEUROLGIC EFFECT bloating, paralytic ileus, urinary - Many drugs can affect the functioning hesitancy and retention, impotence, of the nerves in the periphery and the blurred vision, cycloplegia, CNS. photophobia, headache, mental - Nerves function by using a constant confusion. source of energy to maintain the resting membrane potential and allow INTERVENTIONS excitation. - Provide sugarless lozenges & mouth - This requires glucose, oxygen and a care to help mouth dryness. balance of electrolytes. - Arrange for bowel program as appropriate General central nervous system - Have the patient void before taking the effects drug, to aid voiding. - Some drugs affects neurological - Provide safety measures if vision functioning, either directly or by altering changes occur. electrolyte or glucose levels. - Arrange for medication for headache & - Beta blockers, which are used to treat nasal congestion hypertension, angina, and many other - Advise to avoid hot environments & conditions, can cause feelings of take protective measures to prevent anxiety, insomnia, and nightmares. falling & prevent dehydration. >>>>>>ASSESSMENT - Confusion, delirium, insomnia, PARKINSON-LIKE SYNDROME drowsiness, hyperre exia or - Drugs that directly or indirectly affect hypore exia, bizarre dreams, dopamine levels in the brain can cause hallucinations, numbness, tingling, and a syndrome that resembles paresthesia Parkinson's disease. - Many of the antipsychotic and INTERVENTION neurologic drugs can cause this effect. - provide safety measures - Caution to avoid dangerous situations like driving. - Orient the patient and provide support. fl fl >>>>>>ASSESSMENT - Lack of activity, akinesia, muscular tremors, drooling, changes in gait, rigidity, extreme restlessness or "jitters" (akathisia) , or spasm (dyskinesia). INTERVENTIONS: - Discontinue the drug if needed. - Provide small, frequent meals if swallowing becomes dif cult. - Provide safety measures. NEUROLOGIC MALIGNANT SYNDROME - General anesthetic and other drugs have direct CNS effects can cause neuroleptic malignant syndrome (NMS), generalized syndrome that includes high fever. >>>>>ASSESSMENT - slowed re exes, rigidity, involuntary movements; hyperthermia; and autonomic disturbances, such as hypertension, fast heart rate, and fever. - - INTERVENTIONS: - Discontinue the drug, if necessary - Provide supportive care to lower the body temperature. - Institute safety precautions needed. TERATOGENECITY → Drugs that reach the developing fetus or embryo can cause death or congenital defects. → Before a drug is administered to a pregnant patient the actual bene ts should weighed against the potential risks. fl fi fi

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