McKenna's Pharmacology, 2e

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P A R T 1  Introduction to nursing pharmacology

Interventions Monitor the person’s perceptual losses or changes. Provide protective measures to prevent falling or injury. Consult with the prescriber to decrease the dose or dis­ continue the drug. Provide supportive measures to cope with drug effects. Neurological effects (neurotoxicity) Many drugs can affect the functioning of the nerves in the periphery and the central nervous system. Nerves function by using a constant source of energy to maintain the resting membrane potential and allow excitation. This requires glucose, oxygen and mainte­ nance of electrolyte balance. General central nervous system effects Although the brain is fairly well protected from many drug effects by the blood–brain barrier, some drugs do affect neurological function, either directly or by altering electrolyte or glucose levels. Beta-blockers, which are used to treat hypertension, angina and many other conditions, can cause feelings of anxiety, insomnia and nightmares. Assessment Symptoms may include confusion, delirium, insomnia, drowsiness, hyperreflexia or hyporeflexia, bizarre dreams, hallucinations, numbness, tingling and Provide safety measures to prevent injury. Caution the person to avoid dangerous situations such as driving a car or operating dangerous machinery. Orient the person and provide support. Consult with the prescriber to decrease drug dose or discontinue the drug. Atropine-like (anticholinergic) effects Some drugs block the effects of the parasympathetic nervous system by directly or indirectly blocking cho­ linergic receptors. Atropine, a drug used preoperatively to dry up secretions and any other indications, is the prototype anticholinergic drug. Many cold remedies and antihistamines also cause anticholinergic effects. Assessment Dry mouth, altered taste perception, dysphagia, heart­ burn, constipation, bloating, paralytic ileus, urinary hesitancy and retention, impotence, blurred vision, cycloplegia, photophobia, headache, mental confusion, nasal congestion, palpitations, decreased sweating and dry skin may be noted. Interventions Provide sugarless lozenges and mouth care to help relieve dryness of the mouth. Arrange for a bowel program as appropriate. Have the person void before taking the paraesthesias. Interventions

drug, to aid voiding. Provide safety measures if vision changes occur. Arrange for medication for headache and nasal congestion as appropriate. Advise the person to avoid hot environments and to take protective measures to prevent falling and also dehydration, which may be caused by exposure to heat, owing to decreased sweating. Parkinson-like syndrome (parkinsonism) Drugs that directly or indirectly affect dopamine levels in the brain can cause a syndrome that resembles Parkin­ son’s disease. Many of the antipsychotic and neuroleptic drugs can cause this effect. In most cases, the effects go away when the drug is withdrawn. Assessment Lack of activity, akinesia, muscular tremors, drooling, changes in gait, rigidity, extreme restlessness or “jitters” (akathisia), or spasms (dyskinesia) may be observed. Interventions Discontinue the drug, if necessary. Know that treatment with anticholinergics or antiparkinson drugs may be recommended if the benefit of the drug outweighs the discomfort of its adverse effects. Provide small, frequent meals if swallowing becomes difficult. Provide safety measures if ambulation becomes a problem. Neuroleptic malignant syndrome General anaesthetics and other drugs that have direct central nervous system effects can cause neuroleptic malignant syndrome, a generalised syndrome that includes high fever. Assessment Extrapyramidal symptoms, including slowed reflexes, rigidity, involuntary movements; hyperthermia; and autonomic disturbances, such as hypertension, fast heart rate and fever, may be noted. Interventions Discontinue the drug if necessary. Know that treatment with anticholinergics or antiparkinson drugs may be required. Provide supportive care to lower the body tem­ perature. Institute safety precautions as needed. Teratogenicity Many drugs that reach the developing fetus or embryo can cause death or congenital defects, which can include skeletal and limb abnormalities, central nervous system alterations, heart defects and the like. The exact effects of a drug on the fetus may not be known. In some cases, a predictable syndrome occurs when a drug is given to a pregnant woman. In any situation, inform any pregnant woman who requires drug therapy about the possible effects on the baby. Before a drug is administered to a pregnant woman, the actual benefits should be weighed