Brands, Medical Use, Clinical Data
Drug Category
- Diuretics
- Antihypertensive Agents
Dosage Forms
Brands / Synonyms
Atenolol and Chlorthalidone; Chlorothalidone; Chlorphthalidolone; Chlorphthalidone; Chlortalidone; Chlorthalidon; Chlorthalidone; Clodronic Acid; Clorpres; Edarbyclor; Higroton; Hydro-Long; Hygroton; Igroton; Isoren; Natriuran; Oradil; Phthalamodine; Phthalamudine; Renon; Saluretin; Tenoretic; Thalitone; Zambesil
Indications
For management of hypertension either as the sole therapeutic agent or to enhance the effect of other antihypertensive drugs in the more severe forms of hypertension.
Pharmacology
Chlorthalidone, a monosulfonamyl diuretic, differs form other thiazide diuretics in that a double ring system is incorporated into its structure. Chlorthalidone is used alone or with atenolol in the management of hypertension and edema.
Mechanism of Action
Chlorthalidone inhibits sodium ion transport across the renal tubular epithelium in the cortical diluting segment of the ascending limb of the loop of Henle. By increasing the delivery of sodium to the distal renal tubule, Chlorthalidone indirectly increases potassium excretion via the sodium-potassium exchange mechanism.
Absorption
Absorbed relatively rapidly after oral administration.
Toxicity
Symptoms of overdose include nausea, weakness, dizziness and disturbances of electrolyte balance.
Biotrnasformation / Drug Metabolism
Liver
Contraindications
Anuria.
Known hypersensitivity to chlorthalidone or other sulfonamide-derived drugs.
Drug Interactions
Chlorthalidone may add to or potentiate the action of other antihypertensive drugs. Potentiation occurs with
ganglionic peripheral adrenergic blocking drugs.
Medication such as digitalis may also influence serum electrolytes. Warning signs, irrespective of cause, are:
dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue,
hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting.
Insulin requirements in diabetic patients may be increased, decreased, or unchanged. Higher dosage of oral
hypoglycemic agents may be required. Latent diabetes mellitus may become manifest during chlorthalidone
administration.
Chlorthalidone and related drugs may increase the responsiveness to tubocurarine.
Chlorthalidone and related drugs may decrease arterial responsiveness to norepinephrine. This diminution is not
sufficient to preclude effectiveness of the pressor agent for therapeutic use.
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