triamterene

Triamterene is a medication used in the management and treatment of fluid retention and swelling (edema) associated with various conditions including heart failure, liver or kidney disease, and edema induced by certain medications.

Triamterene may be used alone or with other diuretics such as hydrochlorothiazide, either to enhance their diuretic effect, or for its potassium-sparing property.

Triamterene is a potassium-sparing diuretic that reduces edema by increasing the excretion of sodium and water in the urine, but unlike some of the other classes of diuretics, it does not increase the excretion of potassium and other electrolytes such as calcium, magnesium, and hydrogen. The sodium excretion (natriuresis) and increased urine output (diuresis) reduce water retention and the associated edema. Triamterene can increase blood potassium levels which may sometimes result in hyperkalemia.

Nephron is a functioning unit of the kidneys which filters out waste and reabsorbs minerals like sodium, potassium, and calcium. Triamterene blocks the sodium channels in the cells lining (epithelial) the distal convoluted tubule and collecting duct parts of the nephron, which prevents the reabsorption of sodium and water. The sodium uptake in the distal tubule and connecting duct is limited, hence, triamterene is generally considered to have only weak natriuretic, diuretic and antihypertensive effects.

The uses of triamterene include:

FDA-approved:

• Management of edema in the following conditions:
  • Congestive heart failure
  • Liver cirrhosis
  • Nephrotic syndrome, a kidney disorder that causes excessive protein excretion
  • Steroid-induced edema
  • Edema from an unidentified cause (idiopathic)
  • Edema due to secondary hyperaldosteronism, a condition with high levels of aldosterone, a steroid hormone that inhibits sodium excretion

Off-label

• High blood pressure (hypertension)

• Do not use in patients with hypersensitivity to triamterene or any of its components.
• Do not use in patients with the following conditions:
  • Absence of urine production (anuria)
  • Severe or progressive kidney disease or dysfunction, with the possible exception of nephrosis
  • Severe liver disease
  • High blood potassium levels (hyperkalemia)
• Do not use concurrently with other potassium-sparing diuretics or other formulations containing triamterene.
• Triamterene can cause hyperkalemia, and the risk is higher in patients with impaired kidney function or diabetes, elderly or severely ill patients. Monitor potassium levels at frequent intervals. Discontinue triamterene in patients who develop hyperkalemia, evaluate for irregular heart rhythm conditions (arrhythmia), and treat appropriately.
• Avoid use of diuretics for treatment of elevated blood pressure in patients with primary adrenal insufficiency (Addison disease).
• Do not use triamterene to treat edema normally associated with pregnancy that does not have any pathological cause. Do not use in breastfeeding women.
• There have been isolated reports of hypersensitivity reactions. Monitor patients for blood disorders, liver damage or other reactions.
• Triamterene can cause fluid and electrolyte loss. Monitor patients, particularly those with heart disease, renal disease or liver cirrhosis, for electrolyte disturbances and dehydration, and adjust dose appropriately.
• Use with caution in patients with diabetes mellitus, triamterene may increase blood glucose levels.
• Triamterene may increase uric acid levels, use with caution in patients with high uric acid levels in blood (hyperuricemia) or gout.
• Use with caution in patients with kidney function impairment or a history of kidney stones.
• Use with caution in patients with severe liver dysfunction. Monitor and maintain electrolyte and acid/base balance to prevent brain damage related to liver disease (hepatic encephalopathy).
• Abrupt discontinuation of triamterene after prolonged therapy may cause rebound excretion of potassium in urine (kaliuresis). Withdraw gradually in patients who have received triamterene therapy for prolonged periods.

Common side effects of triamterene include:

• Nausea
• Vomiting
• Diarrhea
• Dry mouth (xerostomia)
• Liver enzyme abnormalities
• Jaundice
• Headache
• Dizziness
• Fatigue
• Weakness
• Skin rash
• Skin photosensitivity
• Severe allergic reaction (anaphylaxis)
• High potassium level in blood (hyperkalemia)
• Low blood potassium (hypokalemia)
• Blood abnormality
• Low red blood cell count with abnormally large red cells (megaloblastic anemia)
• Low platelet count (thrombocytopenia)
• Buildup of waste products in blood (azotemia) including:
  • Blood urea nitrogen (BUN)
  • Creatinine
• Increase in uric acid levels
• Increased acidity of body fluids (metabolic acidosis)
• Kidney stones (nephrolithiasis)
• Rare side effects of triamterene include:
• Acute inflammation in the spaces between the tubules in the kidney (interstitial nephritis)
• Acute kidney failure

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

Capsule

• 50 mg
• 100 mg

Adult:

Edema

• 100-300 mg/day orally every day or divided every 12 hours

Hypertension (Off-label)

• 50-100 mg orally every day or divided every 12 hours

Renal Impairment

• Creatinine clearance (CrCl) less than 10 mL: Do not use

Hepatic Impairment

• Reduce dose in patients with cirrhosis

Other Information

• Monitor serum potassium

Geriatric:

Consider lower initial doses

Edema

• 50-300 mg/day orally every day or divided every 12 hours

Hypertension

• 50-300 mg/day orally every day or divided every 12 hours

Pediatric:

Hypertension (Off-label)

• Safety and efficacy not established
• 1-2 mg/kg/day orally divided every 12 hours
• Maximum dose: 3-4 mg/kg/day orally divided every 12 hours up to 300 mg/day

Overdose

• Triamterene overdose is likely to cause electrolyte imbalance, particularly hypokalemia. Symptoms may include hypotension, weakness, and gastrointestinal disturbances including nausea and vomiting.
• There is no specific antidote for triamterene. Treatment may include stomach emptying with induced vomiting and gastric lavage, and correction of fluid and electrolyte balance.

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Triamterene has no known severe interactions with other drugs.
• Serious interactions of triamterene include:
  • amiloride
  • cyclosporine
  • drospirenone
  • eplerenone
  • lofexidine
  • potassium acid phosphate
  • potassium chloride
  • potassium citrate
  • potassium phosphates, IV
  • spironolactone
• Triamterene has moderate interactions with at least 137 different drugs.
• Triamterene has minor interactions with at least 77 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

• Animal reproductive studies on the safety of triamterene do not indicate fetal harm, however, there are no adequate and well-controlled studies of triamterene use in pregnant women. Triamterene should be used in pregnancy only if clearly needed.
• Triamterene is present in animal milk, and there are no studies in nursing mothers. If triamterene is required for use in nursing mothers, breastfeeding should be discontinued.

• Take triamterene exactly as prescribed, preferably after meals to avoid stomach upset.
• If only one dose is prescribed per day, taking it in the morning will help avoid excessive night time urination.
• Contact your physician if you experience any heart-related symptoms such as irregular or rapid heartbeat.
• Fluid loss can occur with triamterene, drink adequate fluids to avoid dehydration.
• Store safely out of reach of children.
• in case of overdose, seek medical help or contact Poison Control.