Generic
Hydrochlorothiazide + Triamterene
2 brands available in the market
At a glance
Hydrochlorothiazide + Triamterene combination is used for the treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone or in whom the development of hypokalemia cannot be risked.
Description
Hydrochlorothiazide + Triamterene is a combination medicine that helps control hypertension and edema. Hydrochlorothiazide is a thiazide diuretic that removes excess water and sodium from the body. Triamterene is a potassium-sparing diuretic that increases sodium excretion and reduces potassium excretion, preventing hypokalemia. This combination can be used alone or as an adjunct to other antihypertensive drugs such as beta-blockers.
Indications
- Hypertension (high blood pressure)
- Edema - especially in patients who develop hypokalemia on hydrochlorothiazide alone
- In patients in whom the development of hypokalemia cannot be risked
Therapeutic class
Combined antihypertensive preparations
Pharmacological class
Potassium-sparing Diuretic + Thiazide Diuretic
Pharmacology
Triamterene directly inhibits the exchange of Na for K and hydrogen in the distal renal tubule. Hydrochlorothiazide inhibits Na+/Cl- reabsorption in the distal convoluted tubule, increasing sodium and chloride excretion, which reduces plasma volume. Triamterene reduces the kaliuretic effects of other diuretics and adds to the natriuretic effect. It is structurally similar to folate and has anti-folate activity.
Mechanism of action
Triamterene inhibits sodium-potassium exchange in the distal tubule to retain potassium; Hydrochlorothiazide lowers blood pressure by removing excess water through distal tubule sodium reabsorption inhibition.
Dosage
Adult Dose (Oral):
- Hypertension and Edema: 1-2 tablets/capsules (37.5-50 mg triamterene + 25 mg HCTZ) once daily
- Or 1 tablet (75 mg triamterene + 50 mg HCTZ) once daily
- Monitor serum potassium
Child Dose: Safety and efficacy not established
Administration
Take with food; take after meals; take once daily in the morning as directed by your doctor; avoid taking within 4 hours of bedtime; if taking cholesterol-lowering drugs (cholestyramine, colestipol), take this product at least 4 hours before or 4-6 hours after these medications.
Missed dose
If you miss a dose, take it as soon as possible; if it is almost time for your next dose, skip the missed dose and follow regular schedule; do not double the dose.
Side effects
Triamterene: Jaundice, weakness, headache, azotemia, dizziness, fatigue, xerostomia, photosensitivity, rash, diarrhea, nausea, vomiting, hyperuricemia, hyper/hypokalemia, interstitial nephritis
Hydrochlorothiazide: Anorexia, epigastric distress, hypotension, orthostatic hypotension, anaphylaxis, anemia, confusion, erythema multiforme, Stevens-Johnson syndrome, exfoliative dermatitis, dizziness, hypokalemia, hypomagnesemia, hyperuricemia
Others: Arrhythmia, diabetes mellitus, acidosis, hypercalcemia, hyperglycemia, glycosuria, pancreatitis, acute renal failure, leukopenia, thrombocytopenia, muscle cramps, dry mouth, impotence
Precautions & warnings
Precautions:
- Caution in renal and hepatic impairment, cirrhosis, diabetes, hyponatremia, hyperuricemia, history of nephrolithiasis, depleted folic acid stores
- Monitor electrolyte concentrations closely, especially potassium levels
- Observe for signs of liver damage, blood dyscrasias or other idiosyncratic reactions
- Discontinue treatment if urinary calculus is passed
- Pregnancy and elderly: caution
- Lactation: Not recommended; discontinue drug or do not nurse
- Caution in diabetes; thiazides may cause hyperglycemia, glycosuria, and alter insulin requirements
- Caution in hepatic impairment; may precipitate hepatic coma
- Monitor for electrolyte imbalance
Contraindications
Contraindications:
- Severe renal or hepatic impairment
- Preexisting or drug-induced hyperkalemia
- Patients at risk of respiratory or metabolic acidosis
- Lactation
- Antikaliuretic therapy (spironolactone, amiloride) and potassium supplementation
- Anuria, acute and chronic renal insufficiency
- Hypersensitivity
Drug interactions
Drug Interactions:
- May enhance toxicity of digitalis glycosides
- May enhance neuromuscular-blocking action of competitive muscle relaxants
- May enhance effect of antihypertensives
- Increased risk of postural hypotension with alcohol, barbiturates, opioids
- K-depleting effect enhanced by corticosteroids, lithium, ACTH, carbenoxolone
- NSAIDs: May reduce diuretic effect
- Risk of acute renal failure with indomethacin
Food interactions
No food interaction found/established.
Use in pregnancy
Use in Pregnancy: Routine use of diuretics in otherwise healthy woman is inappropriate and exposes mother and fetus to unnecessary hazard; diuretics do not prevent toxemia of pregnancy; indicated when edema is due to pathologic causes.
Use in lactation
Use in Lactation: Triamterene and thiazides appear in breast milk; not recommended; discontinue drug or do not nurse.
Pediatric use
Safety and efficacy not established in pediatric patients.
Geriatric use
Pregnancy and elderly: caution; dose selection for elderly patients should be cautious.
Renal / hepatic impairment
Renal Impairment: Contraindicated in severe renal impairment; anuria, acute and chronic renal insufficiency; caution is advised.
Hepatic Impairment: Caution in hepatic impairment; may precipitate hepatic coma in severe liver disease; caution is advised.
Overdose effects
Overdose: Electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration; hyperkalemia may occur; symptomatic and supportive treatment; gastric lavage should be considered.
Storage conditions
Store at controlled room temperature 20° to 25°C; excursions permitted to 15° to 30°C; protect from light; dispense in a tight, light-resistant container.
Chemical structure
Hydrochlorothiazide + Triamterene