Zestril

Action

Inhibits conversion of angiotensin I to angiotensin II (a potent vasoconstrictor), decreasing systemic vascular resistance, blood pressure, preload, and afterload. Also inactivates bradykinin and other vasodilatory prostaglandins, increases plasma renin levels, and reduces aldosterone levels.

Availability

Tablets: 2.5 mg, 5 mg, 10 mg, 20 mg, 30 mg, 40 mg

Indications and dosages

➣ Hypertension

Adults: Initially, 10 mg P.O. daily, increased to a maintenance dosage of 20 to 40 mg/day. Maximum daily dosage is 80 mg. In patients on diuretics, start with 5 mg/day P.O.

➣ Heart failure

Adults: 5 mg/day P.O. (Prinivil), increased in increments, as ordered, to a maximum of 20 mg/day as a single dose. Or 5 to 40 mg P.O. (Zestril) as a single daily dose given with digitalis and diuretics, increased in increments of no more than 10 mg at intervals of at least 2 weeks, to highest dosage tolerated; maximum dosage is 40 mg/day P.O.

➣ Adjunctive therapy after acute myocardial infarction

Adults: Initially, 5 mg P.O., followed by 5 mg after 24 hours, 10 mg after 48 hours, and then 10 mg daily for 6 weeks (given with standard thrombolytic, aspirin, or beta-adrenergic blocker therapy). If systolic pressure is 120 mm Hg or lower, initial dosage is 2.5 mg for 2 days, then 2.5 to 5 mg/day.

Dosage adjustment

• Impaired renal function

• Heart failure with hyponatremia

Contraindications

• Hypersensitivity to drug or other ACE inhibitors

• Angioedema (hereditary, idiopathic, or ACE-inhibitor induced)

• Pregnancy (second and third trimesters)

Precautions

Use cautiously in:

• renal impairment, hypertension, cerebrovascular or cardiac insufficiency

• family history of angioedema

• concurrent diuretic therapy

• black patients (in whom drug may be less effective in treating hypertension)

• elderly patients

• pregnant patients in first trimester

• breastfeeding patients

• children (safety not established).

Administration

• Give once a day in morning, with or without food.

☞ Measure blood pressure before administering. Withhold drug, if appropriate, according to prescriber's blood pressure parameters. Adjust dosage according to blood pressure response.

• Expect prescriber to add low-dose diuretic if lisinopril alone doesn't control blood pressure.

Adverse reactions

CNS: dizziness, fatigue, headache, asthenia

CV: hypotension, orthostatic hypotension, syncope, chest pain, angina pectoris

GI: nausea, diarrhea, abdominal pain, anorexia

GU: erectile dysfunction, decreased libido, renal dysfunction

Metabolic: hyponatremia, hyperkalemia

Musculoskeletal: myalgia

Respiratory: cough, upper respiratory tract infection, bronchitis, dyspnea, asthma

Skin: rash, pruritus, angioedema

Other: altered taste, fever, anaphylaxis

Interactions

Drug-drug. Cyclosporine, potassium-sparing diuretics, potassium supplements: hyperkalemia

Diuretics, other antihypertensives: excessive hypotension

Indomethacin: reduced antihypertensive effect

Lithium: increased lithium blood level, greater risk of lithium toxicity

Nonsteroidal anti-inflammatory drugs: further deterioration in patients with renal compromise, decreased antihypertensive effects

Thiazides: hypokalemia

Drug-diagnostic tests. Blood urea nitrogen, creatinine, hematocrit, hemoglobin: slightly increased levels

Liver function tests, potassium: increased levels

Sodium: decreased level

Drug-food. Salt substitutes containing potassium: hyperkalemia

Drug-herbs. Capsaicin: cough

Ephedra (ma huang), licorice, yohimbine: antagonistic effects

Drug-behaviors. Acute alcohol ingestion: excessive hypotension

Patient monitoring

• Before and periodically during therapy, monitor CBC with white cell differential and kidney and liver function tests.

☞ Monitor for signs and symptoms of angioedema or anaphylaxis. If these occur, discontinue drug and contact prescriber immediately.

• Check blood pressure frequently to assess drug efficacy. Monitor closely for hypotension, especially in patients also taking diuretics.

• Check vital signs and ECG regularly. Assess cardiovascular status carefully.

• Monitor respiratory and neurologic status.

• Assess potassium intake and blood potassium level.

Patient teaching

• Advise patient to take once a day in morning, with or without food.

☞ Tell patient to immediately report fainting, continuing cough, rash, itching, swelling (especially of face, lips, tongue, or throat), severe dizziness, difficulty breathing, extreme tiredness, or continuing nausea.

☞ Instruct female patient to notify prescriber if she becomes pregnant.

• Tell patient that drug may cause temporary blood pressure decrease if he stands up suddenly. Advise him to rise slowly and carefully.

• Explain that drug may cause muscle aches or headache. Encourage patient to discuss activity recommendations and pain relief with prescriber.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Instruct patient to avoid potassium-based salt substitutes or potassium supplements.

• Tell patient he'll undergo regular blood testing during therapy.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.