Losartan

Losartan

[1 tablet 78 cents]

ADMINISTRATION ROUTES:

  • PO, NG

ALTERNATIVE NAMES:

  • Cozaar, Hyzaar (contains losartan and hydrochlorothiazide)

ICU INDICATIONS:

  1. hypertension
  2. heart failure

PRESENTATION AND ADMINISTRATION:

  • PO / NG:
    Tablets:
    Hyzaar tablets – 50mg losartan, 12.5mg hydrochlorothiazide (yellow) Cozaar 12.5mg tablets (blue), 25mg (white), 50mg (white), 100mg (white)
    Note: tablets can be crushed for administration down NG tubes

DOSAGE:

  • PO:
    Initially 12.5mg daily; increase to maximum of 100mg/day as required

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Start with small dose and adjust cautiously

DOSAGE IN PAEDIATRICS:

  • PO:
    0.5-2mg/kg daily oral

CLINICAL PHARMACOLOGY:

  • Losartan potassium is an angiotensin II receptor (type AT1) antagonist.

CONTRAINDICATIONS:

  1. hypersensitivity to losarten

WARNINGS

  • Volume-Depleted Patients
    In patients who are intravascularly volume-depleted (e.g., those treated with diuretics), symptomatic hypotension may occur after initiation of therapy with losartan.

PRECAUTIONS

  • General:
    • Impaired Hepatic Function
      Based on pharmacokinetic data which demonstrate significantly increased plasma concentrations of losartan in cirrhotic patients, a lower dose should be considered for patients with impaired liver function
    • Impaired Renal Function
      In patients whose renal function may depend on the activity of the renin-angiotensin- aldosterone system (e.g., patients with severe congestive heart failure), treatment with angiotensin converting enzyme inhibitors has been associated with oliguria and/or progressive azotemia and (rarely) with acute renal failure and/or death. Similar outcomes have been reported with losartan potassium. In studies of ACE inhibitors in patients with unilateral or bilateral renal artery stenosis, increases in serum creatinine or BUN have been reported. Similar effects have been reported with losartan potassium; in some patients, these effects were reversible upon discontinuation of therapy. Electrolyte Imbalance Electrolyte imbalances are common in patients with renal impairment, with or without diabetes, and should be addressed. In a clinical study conducted in Type 2 diabetic patients with proteinuria, the incidence of hyperkalemia was higher in the group treated with losartan potassium as compared to the placebo group; however, few patients discontinued therapy due to hyperkalemia.
  • Laboratory Tests:
    No tests are indicated in addition to routine ICU tests
  • Drug/Laboratory Test Interactions:
    None known.

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • As with other drugs that block angiotensin II or its effects, concomitant use of potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, or salt substitutes containing potassium may lead to increases in serum potassium.

ADVERSE REACTIONS

  • Body as a whole:
    Angiooedema, fatigue, anaphylaxis
  • Musculoskeletal:
    Cramp, back pain, rhabdomylosis
  • Cardiovascular:
    Hypotension
  • Metabolic:
    Hyperkalaemia, hyponatraemia
  • Gastrointestinal:
    Hepatitis
  • Urogenital:
    Renal failure

Critical Care Drug Manual

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