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Pharmacologic class: Angiotensin II receptor antagonist
Therapeutic class: Antihypertensive
Pregnancy risk category C (first trimester), D (second and third trimesters)
FDA Box Warning
• When used during second or third trimester of pregnancy, drug may cause fetal harm or death. Discontinue as soon as pregnancy is detected.
Blocks vasoconstricting and aldosterone-secreting effects of angiotensin II at various receptor sites, including vascular smooth muscle and adrenal glands. Also increases urinary flow and enhances excretion of chloride, magnesium, calcium, and phosphate.
Tablets: 25 mg, 50 mg, 100 mg
Indications and dosages
Adults: Initially, 50 mg/day P.O.; range is 25 to 100 mg/day as a single dose or in two divided doses. May be used alone or with other drugs.
Children ages 6 and older: 0.7 mg/kg P.O. daily, up to total of 50 mg
➣ To prevent cerebrovascular accident (stroke) in hypertensive patients with left ventricular hypertrophy (LVH)
Adults: Initially, 50 mg P.O. daily, increased to 100 mg P.O. daily. May be given concurrently with hydrochlorothiazide.
➣ Nephropathy in patients with type 2 diabetes
Adults: 50 mg/day P.O.; increase to 100 mg/day based on blood pressure response.
• Hepatic impairment
• Concurrent diuretic therapy
• Hypersensitivity to drug or its components
• Pregnancy (second and third trimesters)
Use cautiously in:
• heart failure, renal or hepatic impairment, obstructive biliary disorders
• high-dose diuretic therapy
• black patients
• pregnant patients (first trimester) or breastfeeding patients
• children younger than age 6 (safety not established).
• Administer with or without food.
• Know that if drug efficacy (measured at trough) is inadequate with once-daily dosing, prescriber may switch to twice-daily regimen using same or higher daily dosage.
• Be aware that drug may take 3 to 6 weeks to reach maximal efficacy.
CNS: dizziness, insomnia, headache, asthenia, fatigue
EENT: sinus disorders
GI: nausea, vomiting, diarrhea, dyspepsia, abdominal pain
Musculoskeletal: joint pain, back pain, muscle cramps
Respiratory: symptoms of upper respiratory infection, dry cough
Other: hypersensitivity reactions including angioedema
Drug-drug. Diuretics, other antihypertensives: increased risk of hypotension
Fluconazole: inhibited losartan metabolism, increased antihypertensive effects
Indomethacin: decreased losartan effects
Lithium: decreased lithium metabolism
Nonsteroidal anti-inflammatory drugs: decreased renal function
Potassium-sparing diuretics, potassium supplements: hyperkalemia
Rifamycins: enhanced losartan metabolism, decreased antihypertensive effects
Drug-diagnostic tests. Albumin: increased level
Drug-food. Salt substitutes containing potassium: hyperkalemia
☞ Watch for angioedema and other hypersensitivity reactions.
• Monitor blood pressure to evaluate drug efficacy.
• Assess liver and kidney function tests and electrolyte levels.
• Stay alert for oliguria, progressive azotemia, and renal failure in patients with severe heart failure whose renal function depends on the renin-angiotensin-aldosterone system.
• Know that in black patients, losartan and other ACE inhibitors may be ineffective when used alone. Drug isn't indicated for stroke prevention in black hypertensive patients with LVH.
• Be aware that drug may cause fetal injury or death when used during second or third trimester of pregnancy.
• Instruct patient to avoid potassium supplements and salt substitutes containing potassium, unless directed by prescriber.
☞ Caution female patient not to take drug during second or third trimester of pregnancy. Advise her to contact prescriber immediately if she suspects pregnancy.
• Tell female patient to discuss breastfeeding with prescriber before taking.
☞ Instruct patient to immediately report hypersensitivity reactions, especially lip or eyelid swelling, throat tightness, and difficulty breathing.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.
Pharmacologic: angiotensin ii receptor antagonists
Time/action profile (antihypertensive effect†)
|PO||6 hr||3–6 wks||24 hr|
Adverse Reactions/Side Effects
Central nervous system
- chest pain
Ear, Eye, Nose, Throat
- nasal congestion
- weight gain
- diarrhea (most frequent)
- abdominal pain
- impaired renal function
Fluid and Electrolyte
- back pain
- angioedema (life-threatening)
Drug-Drug interactionAdditive hypotension with other antihypertensives.Excessive hypotension may occur with concurrent use of diuretics.↑ risk of hyperkalemia with concurrent use of potassium supplements, potassium-containing salt substitutes, or potassium-sparing diuretics.↑ risk of hyperkalemia, renal dysfunction, hypotension, and syncope with concurrent use of ACE inhibitorsRifampin may ↓ antihypertensive effects.NSAIDs and selective COX-2 inhibitors may blunt the antihypertensive effect and ↑ the risk of renal dysfunction.May increase the effects ofamiodarone, fluoxetine, glimepiride, glipizide, phenytoin, rosiglitazone, sertraline and warfarin.
Hepatic ImpairmentOral (Adults) Hypertension–25 mg once daily initially; may be ↑ as tolerated.
Renal Impairment(Children ≥6 yr) CCr < 30 mL/min—Contraindicated.
Availability (generic available)
- Assess BP (lying, sitting, standing) and pulse frequently during initial dose adjustment and periodically during therapy. Notify health care professional of significant changes.
- Monitor frequency of prescription refills to determine compliance.
- Assess patient for signs of angioedema (dyspnea, facial swelling). May rarely cause angioedema.
- Lab Test Considerations: Monitor renal function. May cause ↑ BUN and serum creatinine.
- May cause ↑ AST, ALT, and serum bilirubin.
- May cause hyperkalemia.
- May cause slight ↓ hemoglobin and hematocrit.
Potential Nursing DiagnosesRisk for injury (Adverse Reactions)
Noncompliance (Patient/Family Teaching)
- Do not confuse Cozaar with Colace or Zocor.
- Correct volume depletion, if possible, before initiation of therapy.
- Oral: For patients with difficulty swallowing tablets, pharmacist can compound an oral suspension; stable for 4 wk if refrigerated. Shake suspension before each use.
- Emphasize the importance of continuing to take as directed, even if feeling well. Take missed doses as soon as remembered if not almost time for next dose; do not double doses. Medication controls but does not cure hypertension. Instruct patient to take medication at the same time each day. Warn patient not to discontinue therapy unless directed by health care professional.
- Caution patient to avoid salt substitutes containing potassium or foods containing high levels of potassium or sodium unless directed by health care professional. See.
- Caution patient to avoid sudden changes in position to decrease orthostatic hypotension. Use of alcohol, standing for long periods, exercising, and hot weather may increase orthostatic hypotension.
- May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
- Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
- Instruct patient to notify health care professional of medication regimen before treatment or surgery.
- Instruct patient to notify health care professional if swelling of face, eyes, lips, or tongue or if difficulty swallowing or breathing occur.
- Advise women of childbearing age to use contraception and notify health care professional if pregnancy is planned or suspected, or if breastfeeding. Losartan should be discontinued as soon as possible when pregnancy is detected.
- Emphasize the importance of follow-up exams to evaluate effectiveness of medication.
- Hypertension: Encourage patient to comply with additional interventions for hypertension (weight reduction, low-sodium diet, discontinuation of smoking, moderation of alcohol consumption, regular exercise, stress management). Medication controls but does not cure hypertension.
- Instruct patient and family on proper technique for monitoring BP. Advise them to check BP at least weekly and to report significant changes.
- Decrease in BP without appearance of excessive side effects.
- Delayed progression of diabetic nephropathy in patients with type 2 diabetes.
- Decreased incidence of stroke in patients with hypertension and left ventricular hypertrophy.