Hydrochlorothiazideinteractions

Agents increasing serum potassium: Risk of hyperkalemia.

Lithium: Risk of lithium toxicity. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): increased risk of renal impairment and reduced diuretic, natriuretic, and antihypertensive effects. Dual inhibition of the renin-angiotensin system: increased risk of renal impairment, hypotension, syncope, and hyperkalemia.

Antidiabetic drugs: dosage adjustment of antidiabetic may be required.

Cholestyramine and colestipol: Reduced absorption of thiazides.

7.1 Agents Increasing

Serum Potassium Coadministration of losartan with other drugs that raise serum potassium levels may result in hyperkalemia. Monitor serum potassium in such patients.

7.2 Lithium

Increases in serum lithium concentrations and lithium toxicity have been reported with concomitant use of angiotensin II receptor antagonists or thiazide diuretics. Monitor lithium levels in patients receiving losartan potassium and hydrochlorothiazide tablets and lithium.

7.3 Non-Steroidal

Anti-Inflammatory Agents Including Selective Cyclooxygenase-2 Inhibitors Losartan Potassium In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including losartan) may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving losartan and NSAID therapy. The antihypertensive effect of angiotensin II receptor antagonists, including losartan, may be attenuated by NSAIDs, including selective COX-2 inhibitors. Hydrochlorothiazide The administration of a non-steroidal anti-inflammatory agent including a selective COX-2 inhibitor can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics. Therefore, when losartan potassium and hydrochlorothiazide tablets and non-steroidal anti-inflammatory agents including selective COX-2 inhibitors are used concomitantly, observe closely to determine if the desired effect of the diuretic is obtained. In patients receiving diuretic therapy, coadministration of NSAIDs with angiotensin receptor blockers, including losartan, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving hydrochlorothiazide, losartan, and NSAID therapy.

7.4 Dual Blockade of the

Renin-Angiotensin System (RAS) Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. The Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial enrolled 1,448 patients with type 2 diabetes, elevated urinary-albumin-to-creatinine ratio, and decreased estimated glomerular filtration rate (GFR 30 to 89.9 mL/min), randomized them to lisinopril or placebo on a background of losartan therapy and followed them for a median of 2.2 years. Patients receiving the combination of losartan and lisinopril did not obtain any additional benefit compared to monotherapy for the combined endpoint of decline in GFR, end-stage renal disease, or death, but experienced an increased incidence of hyperkalemia and acute kidney injury compared with the monotherapy group. Closely monitor blood pressure, renal function, and electrolytes in patients on losartan potassium and hydrochlorothiazide tablets and other agents that affect the RAS. Do not coadminister aliskiren with losartan potassium and hydrochlorothiazide tablets in patients with diabetes. Avoid use of aliskiren with losartan potassium and hydrochlorothiazide tablets in patients with renal impairment (GFR <60 mL/min).

7.5 The Use of

Hydrochlorothiazide with Other Drugs When administered concurrently, the following drugs may interact with thiazide diuretics: Antidiabetic drugs (oral agents and insulin) — dosage adjustment of the antidiabetic drug may be required. Cholestyramine and colestipol resins — Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively. Stagger the dosage of hydrochlorothiazide and the resin such that hydrochlorothiazide is administered at least 4 hours before or 4 to 6 hours after the administration of the resin.