PHARMACOLOGY

Pharmacotherapeutic Group: Diuretics 

Pharmacodynamic properties: Furosemide inhibits reabsorption of Na⁺, Cl^- and K⁺. Spironolactone is a specific antagonist of aldosterone. It increases Na and water excretion but retains K⁺. Thus it acts both as diuretic and an antihypertensive. It reduces oedema and counteracts secondary aldosteronism caused by vol depletion Na loss. K loss is reduced.

Pharmacokinetic properties: Bioavailability : 60%; Half life: 1-2 hrs; Excretion : Urine

  INDICATIONS :  Hypertension, Liver Cirrhosis with Ascitis due to liver cirrhosis, Congestive Heart Failure.  Edema associated with heart failure, renal impairment and nephritic syndrome.

 DOSE :  1-4 tabs/day.

SPECIAL PRECAUTIONS Concomitant use with ACE inhibitors, monitor fluids and electrolytes including changes in serum K levels. Dilutional hyponatraemia or even a true lowsalt syndrome may develop. General anaesthesia.

ADVERSE DRUG REACTIONS :  Fluid and electrolyte imbalance, nausea, diarrhoea, blurred vision, headache, dizziness, hypotension, photosensitisation, hepatic dysfunction, hyperglycaemia and glycosuria, rarely bone marrow depression, gynaecomastia, hirsutism, hoarseness, menstrual irregularities, loss of libido, impotence. Potentially Fatal: Severe hyperkalaemia in patients with preexisting renal impairment or taking ACE inhibitors, agranulocytosis, cardiac arrhythmias.

 DRUG INTERACTIONS :   Aminoglycosides and ethacrynic acid (increased ototoxicity), tubocurazine, succinylcholine (effects enhanced). Sucralfate reduces effects of furosemide. Should be given 2 hr apart. NSAIDs reduce natriuretic and antihypertensive effects of furosemide. Corticosteroids may antagonise action. Digoxin levels may be increased. Warfarin effects may be reduced. Potentially Fatal: Potassium supplements or potassium-rich diet, ACE inhibitors, general anaesthetics (reduced vascular responsiveness to catecholamines), lithium toxicity.

PRESENTATION