Losartan Potassium

Indications

Losartan Potassium is used for: Diabetic nephropathy, Hypertension, Stroke risk reduction of hypertensive or LVH patients, Heart Failure, Hypertensive Patients with Left Ventricular Hypertrophy

Adult Dose

Oral Hypertension Adult: 50 mg once daily, may increase to 100 mg/day as single dose or in 2 divided doses if needed. Patients w/ intravascular volume depletion: Initially, 25 mg once daily. Diabetic nephropathy in Type 2 diabetes mellitus Adult: Initially, 50 mg once daily, may increase to 100 mg once daily depending on BP response. Heart failure, Hypertension and Left Ventricular Hypertrophy, Stroke risk reduction of hypertensive or LVH patients: Adult: Initially, 50 mg once daily. Hydrochlorothiazide 12.5 mg daily should be added and/or the dose of Losartan should be increased to 100 mg once daily followed by an increase in hydrochlorothiazide to 25 mg once daily based on blood pressure response

Child Dose

Hypertension <6 years: Safety and efficacy not established Child: >6 yr 20-50 kg: Initially, 0.7 mg/kg. Max: 50 mg/day; >50 kg: Initially, 1.4 mg/kg. Max: 100 mg/day.

Renal Dose

Renal impairment: CrCl <20 ml/min: Initially 25 mg once daily.

Administration

May be taken with or without food.

Contra Indications

Losartan potassium is contraindicated in patients who are hypersensitive to the active ingredient or any component of the drug. Concomitant use w/ aliskiren in patients w/ diabetes and renal impairment (GFR <60 mL/min). Severe hepatic impairment. Pregnancy.

Precautions

Volume-depleted patients including patients on high-dose diuretics. Patients w/ bilateral renal artery stenosis , aortic or mitral stenosis. Renal and mild to moderate hepatic impairment. Lactation. Monitoring Parameters Monitor BP, electrolytes and renal function. Lactation: Unknown if excreted in milk; not recommended

Pregnancy-Lactation

Pregnancy Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death When pregnancy is detected, discontinue treatment as soon as possible Appropriate management of maternal hypertension during pregnancy is important to optimize outcomes for both mother and fetus Animal data May produce adverse effects in rat fetuses and neonates, including decreased body weight, delayed physical and behavioral development, mortality and renal toxicity With the exception of neonatal weight gain (which was affected at doses as low as 10 mg/kg/day), doses associated with these effects exceeded 25 mg/kg/day (~3x the maximum recommended human dose of 100 mg on a mg/m2 basis) Significant levels of losartan and its active metabolite were present in rat fetal plasma during late gestation and in rat milk Lactation Unknown whether drug is excreted in human milk, but significant levels of losartan and its active metabolite were shown to be present in rat milk

Interactions

May decrease plasma levels / fluconazole and rifampicin. May increase serum lithium levels and toxicity. May antagonise hypotensive effect and increase risk of renal impairment w/ NSAIDs. Increased risk of hyperkalaemia w/ K-sparing diuretics (e.g. amiloride, triamterene, spironolactone), K supplements or K-containing salt substitutes. Potentially Fatal: May increase nephrotoxic, hyperkalaemic and hypotensive effect w/ aliskiren in patients w/ diabetes and renal impairment (GFR <60 mL/min).

Adverse Effects

Side effects of Losartan Potassium : >10% Fatigue (14%), Hypoglycemia (14%), Anemia (14%), Urinary tract infection (UTI) (13%), Chest pain (12%), Weakness (14%), Diarrhea (2-15%), Cough; incidence higher in previous cough related to angiotensin-converting enzyme (ACE) inhibitor therapy (3-11%) 1-10% Upper respiratory tract infection (8%), Hypotension (7%), Dizziness (4%), Cellulitis (7%), Gastritis (5%), Nausea (2%) Frequency Not Defined Angioedema, Edema/swelling, Hypotension in hypovolemic or diuretic-using patients, Asthenia, Headache, Malaise, Nausea, Abdominal pain, Hyperkalemia, Back pain, Worsening renal failure

Mechanism of Action

Losartan is an angiotensin II receptor antagonist. It selectively and competitively blocks the vasoconstricting and aldosterone-secreting effects of angiotensin II by selectively antagonising its binding to AT1 receptors.