Althiazide

Althiazide is a thiazide diuretic used primarily in the treatment of hypertension and edema associated with congestive heart failure, cirrhosis of the liver, and renal dysfunction.

Pharmacology

Mechanism of Action

Althiazide works by inhibiting the sodium-chloride symporter in the distal convoluted tubule of the nephron in the kidney. This action reduces the reabsorption of sodium and chloride ions, leading to increased excretion of sodium, chloride, and water. The diuretic effect of althiazide results in decreased plasma volume, reduced cardiac output, and ultimately lower blood pressure.

Pharmacokinetics

Althiazide is administered orally and is well absorbed from the gastrointestinal tract. It is extensively bound to plasma proteins and is metabolized in the liver. The elimination half-life of althiazide varies depending on renal function, and it is primarily excreted in the urine.

Clinical Uses

Hypertension

Althiazide is commonly prescribed for the management of hypertension. By reducing blood volume and peripheral vascular resistance, it effectively lowers blood pressure. It is often used in combination with other antihypertensive agents such as ACE inhibitors or beta-blockers.

Edema

Althiazide is also indicated for the treatment of edema associated with congestive heart failure, cirrhosis, and nephrotic syndrome. It helps to reduce fluid accumulation in tissues by promoting diuresis.

Adverse Effects

Electrolyte Imbalance

The use of althiazide can lead to electrolyte imbalance, including hypokalemia, hyponatremia, and hypomagnesemia. Patients are often monitored for these imbalances, and supplementation may be necessary.

Metabolic Effects

Althiazide can cause hyperglycemia and hyperlipidemia, which may be of concern in patients with diabetes mellitus or dyslipidemia.

Other Side Effects

Other potential side effects include dizziness, headache, nausea, and rash. Rarely, it can cause pancreatitis or blood dyscrasias.

Contraindications

Althiazide is contraindicated in patients with anuria, severe renal impairment, or known hypersensitivity to thiazides or sulfonamide-derived drugs.

Drug Interactions

Althiazide may interact with other medications, including lithium, NSAIDs, and digoxin. These interactions can affect the efficacy and safety of the treatment.

Monitoring

Patients on althiazide therapy should be regularly monitored for blood pressure, renal function, and electrolyte levels. Adjustments in dosage or additional treatments may be necessary based on these parameters.

Conclusion

Althiazide is an effective thiazide diuretic used in the management of hypertension and edema. Its use requires careful monitoring to avoid potential adverse effects and interactions.