McKenna's Pharmacology for Nursing, 2e

169

C H A P T E R 1 2  Antiprotozoal agents

Cultural considerations

Care considerations for people receiving antimalarial agents

BOX 12.4

on CNS control of vomiting caused by the products of cell death and protein changes. Hepatic dysfunction is associated with the toxic effects of the drug on the liver and the effects of the disease on the liver. Dermatological effects include rash, pruritus and loss of hair associated with changes in protein synthesis of the hair follicles. Visual changes, including possible blindness related to retinal damage from the drug, and ototoxicity related to other nerve damage may occur. Cinchonism (nausea, vomiting, tinnitus and vertigo) may occur with high levels of hydroxychloroquine or primaquine. Clinically important drug–drug interactions The person who is receiving combinations of the quinine derivatives and quinine is at increased risk for cardiac toxicity and convulsions. Therefore, monitor the person closely, checking drug levels and anticipating dose adjustments as needed. be questioned about any history of potential G6PD deficiency. If no history is known, the person should be tested before any of these drugs are prescribed. If testing is not possible and the drugs are needed, the person should be monitored very closely and informed about the potential need for hospitalisation and emergency services. Prototype summary: Hydroxychloroquine Indications: Treatment and prophylaxis of acute attacks of malaria caused by susceptible strains of Plasmodium ; treatment of extraintestinal amoebiasis. Actions: Inhibits protozoal reproduction and protein synthesis. Pharmacokinetics: Route Onset Peak Duration Oral Varies 1–2 hours 1 week T 1/2 : 70 to 120 hours; metabolised in the liver and excreted in the urine. Adverse effects: Visual disturbances, retinal changes, abdominal pain, nausea, vomiting, diarrhoea, skin rashes. Potential for haemolytic crisis People with glucose-6-phosphate dehydrogenase (G6PD) deficiency—which is more likely to occur in Greeks, Italians and other people of Mediterranean descent— may experience a haemolytic crisis if they are taking the antimalarial agent chloroquine or primaquine. People of Greek, Italian or other Mediterranean ancestry should

Assessment: History and examination

■ ■ Assess for contraindications or cautions: history of allergy to any of the antimalarials to prevent hypersensitivity reactions ; liver dysfunction or alcoholism that might interfere with the metabolism and excretion of the drug ; porphyria or psoriasis, which could be exacerbated by the drug effects ; retinal disease that could increase the visual disturbances associated with these drugs ; and pregnancy and breastfeeding because these drugs could affect the fetus and could enter the breast milk and be toxic to the infant . ■ ■ Perform a physical assessment to establish baseline data for assessment of the effectiveness of the drug and the occurrence of any adverse effects associated with drug therapy . Assess CNS (reflexes and muscle strength). ■ ■ Perform ophthalmic and retinal examinations and auditory screening to determine the need for cautious administration and to evaluate changes that occur as a result of drug therapy . ■ ■ Assess the person’s liver function, including liver function tests to determine appropriateness of therapy and to monitor for toxicity . ■ ■ Obtain blood culture to identify the causative Plasmodium species . ■ ■ Inspect the skin closely for colour, temperature, texture and evidence of lesions to monitor for adverse effects . Implementation with rationale ■ ■ Arrange for appropriate culture and sensitivity tests before beginning therapy to ensure proper drug for susceptible Plasmodium species . Treatment may begin before test results are known. ■ ■ Administer the complete course of the drug to get the full beneficial effects . Mark a calendar for prophylactic doses. Use combination therapy as indicated. ■ ■ Monitor hepatic function and perform ophthalmological examination before and periodically during treatment to ensure early detection and prompt intervention with cessation of drug if signs of failure or deteriorating vision occur . ■ ■ Provide comfort and safety measures if CNS effects occur (e.g. side rails and assistance with ambulation if dizziness and weakness are present) to prevent injury . Provide oral hygiene and ready access to bathroom facilities as needed to cope with GI effects .