Home Drug Guide Losartan Potassium

Drug Guide

Generic Name

Losartan Potassium

Brand Names Cozaar, Arbli

Classification

Therapeutic: Antihypertensive, Angiotensin II Receptor Blocker (ARB)

Pharmacological: Competitive AT1 receptor antagonist

FDA Approved Indications

  • Hypertension
  • Reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy
  • Diabetic nephropathy with proteinuria in patients with type 2 diabetes

Mechanism of Action

Losartan blocks the binding of angiotensin II to the AT1 receptor, resulting in vasodilation, decreased aldosterone secretion, and reduction in blood pressure; it also reduces glomerular hypertension in diabetic nephropathy.

Dosage and Administration

Adult: Typically 50 mg once daily, titrated up to 100 mg once daily based on response and tolerability.

Pediatric: Not recommended for children under 6 years. Dosing for older children depends on weight and clinical condition.

Geriatric: Start at lower dose due to increased sensitivity and risk of hypotension.

Renal Impairment: Adjust dose in patients with renal impairment; may be used cautiously.

Hepatic Impairment: Use with caution; no specific dose adjustment required.

Pharmacokinetics

Absorption: Well absorbed from GI tract, with about 33% bioavailability.

Distribution: Widely distributed, crosses placenta.

Metabolism: Metabolized in the liver to an active metabolite, EXP3174.

Excretion: Excreted primarily via urine and feces.

Half Life: Approximately 2 hours for losartan; active metabolite has a half-life of about 6-9 hours.

Contraindications

  • Pregnancy (especially 2nd and 3rd trimesters)
  • History of hypersensitivity to losartan or other ARBs

Precautions

  • Pregnancy category D, caution in patients with bilateral renal artery stenosis, hepatic impairment, volume-depleted states

Adverse Reactions - Common

  • Dizziness (Common)
  • Hyperkalemia (Common)
  • Arthralgia (Less common)

Adverse Reactions - Serious

  • Angioedema (Rare)
  • Hypotension (Rare)
  • Elevated serum creatinine or blood urea nitrogen (BUN) (Rare)

Drug-Drug Interactions

  • Other antihypertensives, potassium-sparing diuretics, lithium, NSAIDs

Drug-Food Interactions

  • Avoid potassium-rich supplements or salt substitutes containing potassium

Drug-Herb Interactions

  • Potential interactions with herbal supplements affecting blood pressure or potassium levels

Nursing Implications

Assessment: Monitor blood pressure, serum potassium, renal function (BUN, serum creatinine) regularly.

Diagnoses:

  • Risk for electrolyte imbalance
  • Risk for hypotension

Implementation: Administer as prescribed, monitor patient response, educate about symptom reporting.

Evaluation: Assess blood pressure for effectiveness; monitor for signs of hyperkalemia or renal impairment.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Do not discontinue without consulting healthcare provider.
  • Avoid potassium supplements or salt substitutes unless directed.
  • Report symptoms like swelling, dizziness, or irregular heartbeat.

Special Considerations

Black Box Warnings:

  • Pregnancy-associated morbidity and fetal death—discontinue as soon as pregnancy is detected.

Genetic Factors: Genetic polymorphisms may influence response to therapy.

Lab Test Interference: May increase serum potassium and serum creatinine.

Overdose Management

Signs/Symptoms: Severe hypotension, tachycardia or bradycardia, electrolyte disturbances.

Treatment: Supportive care, monitor vital signs, correct electrolyte imbalances, administer vasopressors if needed.

Storage and Handling

Storage: Store at room temperature, away from moisture and light.

Stability: Stable for 2-3 years when stored properly.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.