LISINOPRIL

LISINOPRIL (ly-sin'o-pril) Prinivil, Zestril Classifications: angiotensin-converting enzyme (ace) inhibitor; antihypertensive agent; Therapeutic: antihypertensive agent; ace inhibitor Prototype: Enalapril Pregnancy Category: C first trimester; D second and third trimester

Availability

2.5 mg, 5 mg, 10 mg, 20 mg, 30 mg, 40 mg tablets

Action

Lowers BP by specific inhibition of the angiotensin-converting enzyme (ACE). This interrupts conversion sequences initiated by renin that form angiotensin II, a potent vasoconstrictor. ACE inhibition alters hemodynamics without compensatory reflex tachycardia or changes in cardiac output (except in patients with CHF).

Therapeutic Effect

Improved cardiac output and exercise tolerance due to inhibition of ACE also decreases circulating aldosterone, which is normally released in response to angiotensin II stimulation. Reduced aldosterone is associated with a potassium-sparing effect. Also decreases peripheral resistance (afterload) and pulmonary vascular resistance.

Uses

Hypertension, alone or concomitantly with other classes of antihypertensive agents; CHF; to improve MI survival.

Contraindications

Patients with a history of angioedema related to treatment with an ACE inhibitor, ACE inhibitor hypersensitivity; pregnancy (C first trimester, category D second and third trimester), children <6 y; lactation.

Cautious Use

Impaired kidney function, renal artery stenosis, renal disease, renal failure, hyperkalemia, patients on diuretic therapy; aortic stenosis, cardiomyopathy; cerebrovascular disease; collagen vascular disease; coronary artery disease, dialysis; older adults; heart failure, hyperkalemia, hypotension, hypovolemia; African Americans; autoimmune diseases, especially systemic lupus erythematosus (SLE).

Route & Dosage

Hypertension Adult: PO 10 mg once/d, may increase up to 20–40 mg 1–2 times/d (max: 80 mg/d) Child (6–16 y): PO Start at 0.07 mg/kg (max 5 mg) once/d (max: 40 mg/d) Geriatric: PO Initial 2.5–5 mg/d, may increase by 2.5–5 mg/d every 1–2 wk (max: 40 mg/d) Heart Failure Adult: PO 5–40 mg/d

Administration

Oral

• Give an initial dose of 5 mg for diuretic-treated patients. Monitor drug effect for 2 h or until the BP is stabilized for at least 1 additional hour. Concurrent administration with a diuretic may compound hypotensive effect.
• Give before dialysis; lisinopril is removed from blood by hemodialysis.
• Store away from both moisture and heat.

Adverse Effects (≥1%)

CNS: Headache, dizziness, fatigue. CV: Hypotension, chest pain. GI: Nausea, vomiting, diarrhea, anorexia, constipation, intestinal angioedema. Hematologic: Neutropenia. Respiratory: Dyspnea, cough. Skin: Rash. Metabolic: Azotemia, hyperkalemia, increased BUN, and creatinine levels.

Interactions

Drug: Indomethacin and other nsaids may decrease antihypertensive activity; potassium supplements, potassium-sparing diuretics may cause hyperkalemia; may increase lithium levels and toxicity.

Pharmacokinetics

Absorption: 25% absorbed from GI tract. Onset: 1 h. Peak: 6–8 h. Duration: 24 h. Distribution: Limited amount crosses blood–brain barrier; crosses placenta; small amount distributed in breast milk. Metabolism: Is not metabolized. Elimination: Primarily in urine. Half-Life: 12 h.

Nursing Implications

Assessment & Drug Effects

• Place patient in supine position and notify physician if sudden and severe hypotension occurs within the first 1–5 h after initial drug dose; possible particularly in patients who are sodium- or volume-depleted because of diuretic therapy.
• Measure BP just prior to dosing to determine whether satisfactory control is being maintained for 24 h. If the antihypertensive effect is diminished in less than 24 h, an increase in dosage may be necessary.
• Monitor closely for angioedema of extremities, face, lips, tongue, glottis, and larynx. Discontinue drug promptly and notify physician if such symptoms appear; carefully monitor for airway obstruction until swelling is relieved.
• Monitor serum sodium and serum potassium levels for hyponatremia and hyperkalemia.
• Lab tests: Determine WBC count prior to initiation of treatment, every month for the first 3–6 mo of therapy, and at periodic intervals for 1 y. Withhold therapy and notify physician if neutropenia (neutrophil count <1000/mm³) develops; kidney function tests at periodic intervals, especially in patients with severe volume or sodium replacement or those with severe CHF.

Patient & Family Education

• Discontinue drug and contact physician immediately for severe hypersensitivity reaction (e.g., hoarseness, swelling of the face, mouth, hands, or feet, or sudden trouble breathing).
• Be aware of importance of proper diet, including sodium and potassium restrictions. Do NOT use salt substitute containing potassium.
• Continued compliance with high BP medication is very important. If a dose is missed, take it as soon as possible but not too close to next dose.
• Do not drive or engage in other potentially hazardous activities until response to the drug is known.
• With concomitant therapy, lisinopril increases the risk of lithium toxicity.
• Notify physician promptly of any indication of infection (e.g., sore throat, fever).
• Do not store drug in a moist area. Heat and moisture may cause the medicine to break down.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug