For treatment of high blood pressure, you must take chlorothiazide regularly for it to be effective. As blood pressure declines gradually, it can take several weeks before you experience the full benefit of chlorothiazide, and you must continue taking it even if you are feeling well. Note that chlorothiazide does not cure high blood pressure, it simply keeps it under control.
When given concurrently the following drugs may interact with thiazide diuretics.
- Alcohol, barbiturates, or narcotics: Potentiation of otthostatic hypotension may occur.
- Antidiabetic drugs: (Oral agents and insulin) Dosage adjustment of the antidiabetic drug may be required.
- Other antihypertensive drugs: Additive effect or potentiation.
- Cholestyramine and colestipol resins: Cholestytamine and colestipol resins have the potential of binding thiazide diuretics and reducing diuretic absorption from the gastrointestinal tract.
- Corticosteroids, ACTH: Intensified electrolyte depletion, particularly hypokalemia.
- Pressor amines (e.g., norepinephrine): Possible decreased response to pressor amines but not sufficient to preclude their use.
- Skeletal muscle relaxants, nondepolarizing (e.g., tubocurarine): Possible increased responsiveness to the muscle relaxant.
- Lithium: Generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Refer to the package insert for lithium preparations before use of such preparations with chlorothiazide.
- Non-steroidal Anti-inflammatory Drugs: In some patients, the administration of a non-steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when chlorothiazide and non-steroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.
- Drug/Laboratory Test Interactions: Thiazides should be discontinued before carrying out tests for parathyroid function.
Hypersensitivity to this or other sulfonamide-derived drugs.