Hydrochlorothiazideinteractions

Lithium: Risk of lithium toxicity Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Reduced diuretic, natriuretic and antihypotensive effects; increased risk of renal toxicity Dual inhibition of the renin-angiotensin system: Increased risk of renal impairment, hypotension, and hyperkalemia Colesevelam hydrochloride: Consider administering olmesartan at least 4 hours before colesevelam hydrochloride dose Antidiabetic drugs: Dosage adjustment may be required Cholestyramine and colestipol: Reduced absorption of thiazides

7.1 Agents Increasing

Serum Potassium Coadministration of olmesartan medoxomil and hydrochlorothiazide 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 during concomitant administration of lithium with angiotensin II receptor antagonists or hydrochlorothiazide. Monitor serum lithium levels during concomitant use. 7. 3 Non-Steroidal Anti-Inflammatory Agents including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) Olmesartan medoxomil In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including olmesartan medoxomil) may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving olmesartan medoxomil and NSAID therapy. The antihypertensive effect of angiotensin II receptor antagonists, including olmesartan medoxomil may be attenuated by NSAIDs including selective COX-2 inhibitors. Hydrochlorothiazide In some patients the administration of a NSAID can reduce the diuretic, natriuretic, and antihypertensive effects of thiazide diuretics. Therefore, monitor blood pressure closely.

7.4 Dual Blockade of the

Renin Angiotensin System Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Most patients receiving the combination of two RAS inhibitors do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAS inhibitors. Closely monitor blood pressure, renal function and electrolytes in patients on olmesartan medoxomil and hydrochlorothiazide and other agents that affect the RAS. Do not co-administer aliskiren with olmesartan medoxomil and hydrochlorothiazide in patients with diabetes. Avoid use of aliskiren with olmesartan medoxomil and hydrochlorothiazide in patients with renal impairment (GFR <60 ml/min).

7.5 Colesevelam H ydrochloride

Concurrent administration of bile acid sequestering agent colesevelam hydrochloride reduces the systemic exposure and peak plasma concentration of olmesartan. Administration of olmesartan at least 4 hours prior to colesevelam hydrochloride decreased the drug interaction effect. Consider administering olmesartan at least 4 hours before the colesevelam hydrochloride dose. 7. 6 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.

Ion exchange resins: Staggering the dosage of hydrochlorothiazide and ion exchange resins (e.g., cholestyramine, colestipol) such that hydrochlorothiazide is administered at least 4 hours before or 4 – 6 hours after the administration of resins would potentially minimize the interaction. Corticosteroids, ACTH: Intensified electrolyte depletion, particularly hypokalemia.