Drug Interactions Chlorthalidone may add to or potentiate the action of other antihypertensive drugs.
Insulin requirements in diabetic patients may be increased, decreased or unchanged. Higher dosage of oral hypoglycemic agents may be required.
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.
Lithium renal clearance is reduced by chlorthalidone, increasing the risk of lithium toxicity.