indication

Polythiazide is a thiazide diuretic used to decrease edema and decrease blood pressure.

pharmacology

As a thiazide diuretic, Polythiazide inhibits the sodium-chloride symporter which decreases solute reabsorption leading to a retention of water in the urine, as water normally follows solutes. More frequent urination is due to the increased loss of water that has not been retained from the body as a result of a concomitant relationship with sodium loss from the convoluted tubule. The short-term anti-hypertensive action is based on the fact that thiazides decrease preload, decreasing blood pressure

mechanism of action

As a diuretic, polythiazide inhibits active chloride reabsorption at the early distal tubule via the thiazide-sensitive Na-Cl cotransporter (TSC), resulting in an increase in the excretion of sodium, chloride, and water. Thiazides like polythiazide also inhibit sodium ion transport across the renal tubular epithelium through binding to the thiazide sensitive sodium-chloride transporter. This results in an increase in potassium excretion via the sodium-potassium exchange mechanism. The antihypertensive mechanism of polythiazide may be mediated through its action on carbonic anhydrases in the smooth muscle or through its action on the large-conductance calcium-activated potassium (KCa) channel, also found in the smooth muscle.

drug interactions

Digoxin: Possible electrolyte variations and arrhythmias

Lithium: The thiazide diuretic, polythiazide, may increase serum levels of lithium.

Trandolapril: The thiazide diuretic, Polythiazide, may increase the hypotensive effect of Trandolapril. Polythiazide may also increase the nephrotoxicity of Trandolapril. Monitor for postural hypotension at initiation of concomitant therapy and renal dysfunction during chronic therapy.

Treprostinil: Additive hypotensive effect. Monitor antihypertensive therapy during concomitant use.