Potasium sparing diuretics include 

Spironolactone, Amiloride, Traimterene

Refer Spironolactone

Interacting drugs- summary

+ Amiloride

 Digoxin

amiloride increased the renal clearance and decreased the non-renal clearance of digoxin in six healthy subjects.

Potassium preparations

 concurrent administration may result in severe hyperkalemia and possibly with cardiac arrhythmias or cardiac arrest. Avoid concurrent use. 

 ACE inhibitors

 use of ACE inhibitors result in elevated serum potassium concentration. Concurrent use with amiloride may lead to significant hyperkalemia.

Salicylates

the diuretic effect of spironolactone decrease by concurrent salicylate use, possibly due to reduced tubular secretion of canrenone , this interaction is dose dependent. The antihypertensive action dose not appear altered.

Increased risk of hyperkalalemia in patients on oral hypoglycemic agents, potassium sparing diuretics, potassium supplement.

Risk of lithium toxicity. Increased risk of hyponatraemia with chlorpropamide.

Interferes with ulcer healing by carbenoxolone.

NSAIDs may diminish anti-hypertensive effects.

Decreased digoxin clearance.

Adjunctive treatment with thiazide or loop diuretics in congestive heart failure.

Potasium sparing diuretics include 

Spironolactone, Amiloride, Traimterene

Refer Spironolactone

FIXED DOSE COMBINATIONS APPROVED BY DCG(I)                                           FROM JANUARY 1961 TILL NOVEMBER 2014

CNS

Headache, dizziness, encephalopathy, paresthesia, tremors, vertigo, nervousness, mental confusion, insomnia,decreased libido, depression,somnolence

GI

Nausea, anorexia, vomying, abdominal pain, gas pain, appetite changes, constipation,jaundice, GI bleeding, GI disturbance, abdominal fullness, dry mouth, heartburn, faltulence, dyspepsia, activation of probable pre-existing peptic ulcer, abnormal liver function.

Metabolic

Elevated serum potassium levels

Musculoskelatal

Weakness, fatigue, muscle carmps, joint back/neck pain, neckor shoulder ache, pain of the extremities.

Respiratory

Cough, dyspnea, shortness of breath.

GU

Impotence, polyuria, dysuria, urinary frequency, bladder spasms.

Cardiovascular-

angina pectoris, orthostatic hypotension, arrhythmias, palpitations.

Dermatologic-

skinrash, itching, pruritus, alopecia

Special senses-

visual disturbances, nasal cingestion, tinnitus .increased intraocular pressure

Hematologic-

aplastic anemia, neutropenia

Hyperkalemia,renal failure,anuria,hypersens.

Special precautions:

Potassium sparing diuretics, potassium supplementing, diabetes.

Electroltye imbalance and BUN increases- hyponatremia and hypochloremia may occur when amiloride is used with other diuretics.

Increases in BUN level usally accompany vigorous fluid elimination especially when diuretic therapy is used in seriously ill patients, such as those who have hepatic cirrhosis with ascites and metabolic alakalosis or those with resistent edema.

Carefully monitor serum electrolytes and BUN levels.

Warnings

Hyperkalemia

Amiloride may cause hyperkalemia which if uncorrected is potentailly fatal. Hyperkalemia occurs (about 10%) when amiloride is used alone.

Monitor serum potassium levels carefully, particularly when amiloride is first introduced at the time of diuretic dosage adjustments and, during any illness, that could affect renal function.

Diabetes mellitus

Hyperkalemiaas occured with the use of amiloride even when without evidence of diabetic nephropathy. If possible avoid using amiloride in diabetic patients. If it is used monitor serum elecytrolyes and renal function frequently.

Metabolic or respiratory acidosis

Cauitiously institute amiloride in severly ill patients in whom respiratory or metabolic acidosis may occur. such as patients with cardiopulmonary disease or poorly controlled diabetes. Monitor acid-base balance frequently.

Renal function impairment-

Do not give to patients with evidence of renal impairment (BUN 30mg/dl or serum creatinine . 1.5mg/bl ) or diabetes mellitus without continous moinitoring of serum electrolytes,creatine and BUN levels.

Hepatic function impairment-

Because amiloride is not metabolised by the liver drug accumulation is not anticipated in patients with hepatic dysfunction, but accumulation can occur if hepatorenal syndrome develops.

Pregnancy-

Safety for use during pregnancy has not been established.Use with caution.

Lactation-

Because of the potential for serious adverse reactions in nursing infants, decide whether to discontinue nursing or discontinue the drug taking into consideration the importance of the drug to the mother.

Children-

Safety and efficacy for use in children have not been established

Indications

Adjunctive treatment with thiazide or loop diuretics in congestive heart failure

Dosage

Administer with food. Add Amilloride 5mg/day to usual antihypertensive or diuretic dosage of a kaliuretic diuretic. Increase dosage to 10mg/day, if neccessary.

1. May cause GI upset; .Take with food.

2. Notify physician if any of these symptoms occur - muscular weakness, fatigue, muscle cramps.

3. May cause dizziness, headache, or visual disturbances, observe caution while driving or performing tasks requiring alertness, coordination or physical dexterity.

4. Avoid large quantities of potassium rich food.

Pharmacology:

In the kidney, potassium is filtered at the glomerulus and then absorbed parallel to sodium throughout the proximal tubule and thick ascending limb of the loop of Henie, so that minor amounts reach the distal convoluted tubule. As a result potassium appearing in the urine is secreted at the distal tubule and collecting duct.

The potassium sparing diuretics interfere with sodium reabsorption at the distal tube thus decreasing potassium secretion.

Can be taken with food.

Pregnancy

There are no adequate and well controlled studies conducted in pregnant women. Safety for use in pregnancy has not been established. Use only when required.

Lactation

Not known whether Amiloride is excreted in breast milk. Discontinue the drug taking into consideration the potential adverse reaction in nursing infants.

Children-

Safety and efficacy for use in children have not been established