Names and pronunciation
(a-mill′oh-ride) Midamor
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Drug reference
(a-mill′oh-ride) Midamor
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Func. class.: Potassium-sparing diuretic
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Chem. class.: Pyrazine
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Do not confuse: aMILoride/amLODIPine/amiodarone
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ACTION: Inhibits sodium, potassium ion exchange in the distal tubule, cortical collecting duct, resulting in inhibition of sodium reabsorption and decreasing potassium secretion
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USES: Edema in HF in combination with other diuretics, for hypertension, adjunct with other diuretics to maintain potassium
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CONTRAINDICATIONS: Anuria, hypersensitivity, diabetic nephropathy, renal failure
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Black Box Warning: Hyperkalemia Precautions: Pregnancy, breastfeeding, children, geriatric patients, dehydration, diabetes, respiratory acidosis, hyponatre- mia, impaired renal function Black Box Warning: Hyperkalemia: avoid concurrent use with other po- tassium-sparing diuretics, potassium products, ACE inhibitors, salt substitutes, cycloSPORINE, tacrolimus; if using to- gether, monitor potassium level Increase: lithium toxicity: lithium; moni- tor lithium levels Increase: action of antihypertensives Decrease: effect of aMILoride—NSAIDs; avoid concurrent use Drug/Herb Increase: effect—hawthorn, horse chestnut Drug/Food • Possible hyperkalemia: foods high in potassium, potassium-based salt substitutes Drug/Lab Test Increase: LFTs, BUN, potassium, sodium, bilirubin, calcium, cholesterol Decrease: Potassium, magnesium, sodium Interference: GTT Black Box Warning: Hyperkalemia: fa- tigue, weakness, paresthesia, confusion, dyspnea, dysrhythmias, ECG changes; including hyperacute T waves; monitor potassium level at baseline and dosage changes, hyperkalemia is more com- mon in renal disease, geriatric patients, diabetes; if potassium ≥5.5 mEq/L, im- mediately notify prescriber; discontinue aMILoride 3 days before GTT • Fluid volume status: distended neck veins; crackles in lungs; color, quality, and specific gravity of urine; skin turgor; adequacy of pulse; moist mucous mem- branes; bilateral lung sounds; peripheral pitting edema; dehydration; symptoms of decreasing output; thirst; hypotension; dry mouth should be reported • Hypokalemia: weakness, polyuria, polydipsia, fatigue, ECG U wave • Pregnancy/breastfeeding: identify if pregnancy is planned or suspected or if breastfeeding; use only if clearly needed • Beers: avoid in older adults; may decrease sodium, increase potassium, decrease Ccr; use with caution; may exacerbate or cause inappropriate antidi- uretic hormone secretion/hyponatremia; monitor sodium level carefully
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SIDE EFFECTS CNS: Headache, dizziness, weakness, paresthesias, tremors, depression, anxi- ety, encephalopathy CV: Orthostatic hypotension, dysrhyth- mias, chest pain ELECT: Hyperkalemia, dehydration, hyponatremia GI: Nausea, diarrhea, dry mouth, vom iting, anorexia, cramps, constipation, abdominal pain, jaundice INTEG: Rash, pruritus, Stevens-Johnson syndrome, toxic epidermal necrolysis MS: Cramps
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INTERACTIONS
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TREATMENT OF OVERDOSE: Lavage if taken orally, monitor electro- lytes, administer sodium bicarbonate for potassium >6.5 mEq/L, IV glucose, Kayexalate as needed; monitor hydration, CV, renal status
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DOSAGE AND ROUTES • Adult: PO 5-10 mg/day in 1-2 divided doses; may be increased to 10-20 mg/day if needed • Infant/child (6-20 kg): PO 0.4-0.625 mg/kg daily, max 20 mg/day, dose daily max 20 mg/day Renal dose • Adult: PO CCr 10-50 mL/min reduce dose by 50%; CCr <10 mL/min contraindi- cated
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Available forms: Tablets 5 mg
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Administer: • In AM to avoid interference with sleep if using as diuretic; if second daily dose is needed, give in late afternoon • With food; if nausea occurs, absorp- tion may be decreased slightly
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Assess: • Heart rate; B/P lying, standing; pos- tural hypotension may occur • Electrolytes: potassium, sodium, chloride; glucose (serum), BUN, CBC, serum creatinine, blood pH, ABGs, peri- odic ECG
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Evaluate: • Therapeutic response: improvement in edema of feet, legs, sacral area daily if medication is being used for HF; de- creased B/P; prevention of hypokalemia (diuretics)
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • To take as prescribed; if dose is missed, to take when remembered within 1 hr of next dose; to take with food or milk for GI symptoms; to take early in day to prevent nocturia; to avoid alcohol; not to use other products unless approved by prescriber • To maintain a weekly record of weight, notify health care professional of weight loss >5 lb • About adverse reactions: to report muscle cramps, weakness, nausea, dizzi- ness, blurred vision • Hyperkalemia: to avoid potassium- rich foods: oranges, bananas, salt substi- tutes, dried fruits, potassium supple- ments; refer to dietician for assistance, planning • To rise slowly from sitting to standing to avoid orthostatic hypotension • To avoid hazardous activities if dizzi- ness occurs • To continue other medical treatments (exercise, weight loss, relaxation tech- niques, cessation of smoking) • To continue taking medication even if feeling better, this product controls symptoms but does not cure condition, to use as directed, not to double or skip doses • Not to exercise in hot weather or stand for prolonged periods since orthostatic hypotension is enhanced • How to take own B/P, pulse, and A record
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PHARMACOKINETICS Absorption variable 20%-90%; widely distributed; onset 2 hr; peak 6-10 hr; duration 24 hr; excreted in urine, feces; half-life 6-9 hr, crosses placenta
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• Adult: PO 5-10 mg/day in 1-2 divided doses; may be increased to 10-20 mg/day if needed
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• Infant/child (6-20 kg): PO 0.4-0.625 mg/kg daily, max 20 mg/day, dose daily max 20 mg/day Renal dose
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• Adult: PO CCr 10-50 mL/min reduce dose by 50%; CCr <10 mL/min contraindi- cated
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