Spironolactone Interactions

7 DRUG INTERACTIONS Agents increasing serum potassium: Concomitant administration can lead to hyperkalemia ( 5.1 , 7.1 ). Lithium: Increased risk of lithium toxicity ( 7.2 ). NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of spironolactone ( 7.3 ). Digoxin: spironolactone can interfere with radioimmunologic assays of digoxin exposure ( 7.4) . Cholestyramine: Hyperkalemic metabolic acidosis has been reported with concomitant use ( 7.5 ). Acetylsalicylic Acid (ASA): ASA may reduce the efficacy of spironolactone ( 7.6 ) Abiraterone: May increase prostate-specific antigen (PSA) levels ( 7.7 ). 7.1 Drugs and Supplements Increasing Serum Potassium Concomitant administration of spironolactone with potassium supplementation or drugs that can increase potassium may lead to severe hyperkalemia. In general, discontinue potassium supplementation in heart failure patients who start spironolactone [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3) ] . Check serum potassium levels when ACE inhibitor or ARB therapy is altered in patients receiving spironolactone. Examples of drugs that can increase potassium include: ACE inhibitors angiotensin receptor blockers non-steroidal anti-inflammatory drugs (NSAIDs) heparin and low molecular weight heparin trimethoprim 7.2 Lithium Like other diuretics, spironolactone reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity. Monitor lithium levels periodically when spironolactone is coadministered [see Clinical Pharmacology (12.3) ] . 7.3 Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of diuretics. Therefore, when spironolactone and NSAIDs are used concomitantly, monitor closely to determine if the desired effect of the diuretic is obtained [see Clinical Pharmacology (12.3) ] . 7.4 Digoxin Spironolactone and its metabolites interfere with radioimmunoassays for digoxin and increase the apparent exposure to digoxin. It is unknown to what extent, if any, spironolactone may increase actual digoxin exposure. In patients taking concomitant digoxin, use an assay that does not interact with spironolactone. 7.5 Cholestyramine Hyperkalemic metabolic acidosis has been reported in patients given spironolactone concurrently with cholestyramine. 7.6 Acetylsalicylic Acid Acetylsalicylic acid may reduce the efficacy of spironolactone. Therefore, when spironolactone and acetylsalicylic acid are used concomitantly, spironolactone may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained [see Clinical Pharmacology (12.3) ] . 7.7 Abiraterone Spironolactone binds to the androgen receptor and may increase prostate-specific antigen (PSA) levels in abiraterone-treated prostate cancer patients. Concomitant use of spironolactone and abiraterone is not recommended.

7 DRUG INTERACTIONS • Agents increasing serum potassium: Concomitant administration can lead to hyperkalemia ( 5.1 , 7.1 ). • Lithium: Increased risk of lithium toxicity ( 7.2 ). • NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of spironolactone ( 7.3 ). • Digoxin: Spironolactone can interfere with radioimmunologic assays of digoxin exposure ( 7.4 ). • Cholestyramine: Hyperkalemic metabolic acidosis has been reported with concomitant use ( 7.5 ). • Acetylsalicylic Acid (ASA): ASA may reduce the efficacy of spironolactone ( 7.6 ). • Abiraterone: May increase prostate-specific antigen (PSA) levels ( 7.7 ). • Mitotane: Avoid concomitant use of spironolactone and mitotane ( 7.8 ). 7.1 Drugs and Supplements Increasing Serum Potassium Concomitant administration of spironolactone with potassium supplementation or drugs that can increase potassium may lead to severe hyperkalemia. In general, discontinue potassium supplementation in heart failure patients who start spironolactone [see Warnings and Precautions ( 5.1 ) and Clinical Pharmacology ( 12.3 )] . Check serum potassium levels when ACE inhibitor or ARB therapy is altered in patients receiving spironolactone. Examples of drugs that can increase potassium include: • ACE inhibitors • angiotensin receptor blockers • non-steroidal anti-inflammatory drugs (NSAIDs) • heparin and low molecular weight heparin • trimethoprim 7.2 Lithium Like other diuretics, spironolactone reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity. Monitor lithium levels periodically when spironolactone is coadministered [see Clinical Pharmacology ( 12.3 )] . 7.3 Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of diuretics. Therefore, when spironolactone and NSAIDs are used concomitantly, monitor closely to determine if the desired effect of the diuretic is obtained [see Clinical Pharmacology ( 12.3 )] . 7.4 Digoxin Spironolactone and its metabolites interfere with radioimmunoassays for digoxin and increase the apparent exposure to digoxin. It is unknown to what extent, if any, spironolactone may increase actual digoxin exposure. In patients taking concomitant digoxin, use an assay that does not interact with spironolactone. 7.5 Cholestyramine Hyperkalemic metabolic acidosis has been reported in patients given spironolactone concurrently with cholestyramine. 7.6 Acetylsalicylic Acid Acetylsalicylic acid may reduce the efficacy of spironolactone. Therefore, when spironolactone and acetylsalicylic acid are used concomitantly, spironolactone may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained [see Clinical Pharmacology ( 12.3 )] . 7.7 Abiraterone Spironolactone binds to the androgen receptor and may increase prostate-specific antigen (PSA) levels in abiraterone-treated prostate cancer patients. Concomitant use of spironolactone and abiraterone is not recommended. 7.8 Mitotane Avoid concomitant use of spironolactone and mitotane. Spironolactone reduces mitotane plasma levels [see Clinical Pharmacology ( 12.3 )] .

Drug interactions ACE inhibitors, Angiotensin II receptor antagonists, aldosterone blockers, potassium supplements, heparin, low molecular weight heparin, and other drugs known to cause hyperkalemia Concomitant administration may lead to severe hyperkalemia. Alcohol, barbiturates, or narcotics Potentiation of orthostatic hypotension may occur. Antidiabetic drugs (e.g., oral agents, insulin) Dosage adjustment of the antidiabetic drug may be required (see Precautions ). Corticosteroids, ACTH Intensified electrolyte depletion, particularly hypokalemia, may occur. Pressor amines (e.g., norepinephrine) Both spironolactone and hydrochlorothiazide reduce the vascular responsiveness to norepinephrine. Therefore, caution should be exercised in the management of patients subjected to regional or general anesthesia while they are being treated with spironolactone and hydrochlorothiazide. Skeletal muscle relaxants, nondepolarizing (e.g., tubocurarine) Possible increased responsiveness to the muscle relaxant may result. Lithium Lithium generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. Nonsteroidal anti-inflammatory drugs (NSAIDs) In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing, and thiazide diuretics. Combination of NSAIDs, e.g., indomethacin, with potassium-sparing diuretics has been associated with severe hyperkalemia. Therefore, when spironolactone and hydrochlorothiazide tablets and NSAIDs are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained. Acetylsalicylic acid Acetylsalicylic acid may reduce the efficacy of spironolactone. Therefore, when spironolactone and hydrochlorothiazide tablets and acetylsalicylic acid are used concomitantly, spironolactone and hydrochlorothiazide tablets may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained. Digoxin Spironolactone has been shown to increase the half-life of digoxin. This may result in increased serum digoxin levels and subsequent digitalis toxicity. Monitor serum digoxin levels and adjust dose accordingly. Thiazide-induced electrolyte disturbances, i.e. hypokalemia, hypomagnesemia, increase the risk of digoxin toxicity, which may lead to fatal arrhythmic events (see Precautions ) Cholestyramine Hyperkalemic metabolic acidosis has been reported in patients given spironolactone concurrently with cholestyramine. Abiraterone Spironolactone binds to the androgen receptor and may increase prostate-specific antigen (PSA) levels in abiraterone-treated prostate cancer patients. Concomitant use of spironolactone is not recommended. Mitotane Avoid concomitant use of spironolactone and hydrochlorothiazide tablets and mitotane. Spironolactone reduces mitotane plasma levels. The effect of concomitant spironolactone on the pharmacokinetics of mitotane has not been studied; however, patients exhibited significantly lower mitotane levels compared to those who did not receive concomitant spironolactone despite receiving higher mitotane doses.

7 DRUG INTERACTIONS Agents increasing serum potassium: Concomitant administration can lead to hyperkalemia ( 5.1 , 7.1 ). Lithium: Increased risk of lithium toxicity ( 7.2 ). NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of spironolactone tablets ( 7.3 ). Digoxin: Spironolactone tablets can interfere with radioimmunologic assays of digoxin exposure ( 7.4 ). Cholestyramine: Hyperkalemic metabolic acidosis has been reported with concomitant use ( 7.5 ). Acetylsalicylic Acid (ASA): ASA may reduce the efficacy of spironolactone tablets ( 7.6 ). 7.1 Drugs and Supplements Increasing Serum Potassium Concomitant administration of spironolactone tablets with potassium supplementation or drugs that can increase potassium may lead to severe hyperkalemia. In general, discontinue potassium supplementation in heart failure patients who start spironolactone tablets [ see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3) ] . Check serum potassium levels when ACE inhibitor or ARB therapy is altered in patients receiving spironolactone tablets. Examples of drugs that can increase potassium include: ACE inhibitors angiotensin receptor blockers non-steroidal anti-inflammatory drugs (NSAIDs) heparin and low molecular weight heparin trimethoprim 7.2 Lithium Like other diuretics, spironolactone tablets reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity. Monitor lithium levels periodically when spironolactone tablets are coadministered [ see Clinical Pharmacology (12.3) ] . 7.3 Nonsteroidal anti-inflammatory drugs (NSAIDs) In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of diuretics. Therefore, when spironolactone tablets and NSAIDs are used concomitantly, monitor closely to determine if the desired effect of the diuretic is obtained [ see Clinical Pharmacology (12.3) ] . 7.4 Digoxin Spironolactone and its metabolites interfere with radioimmunoassays for digoxin and increase the apparent exposure to digoxin. It is unknown to what extent, if any, spironolactone may increase actual digoxin exposure. In patients taking concomitant digoxin, use an assay that does not interact with spironolactone. 7.5 Cholestyramine Hyperkalemic metabolic acidosis has been reported in patients given spironolactone tablets concurrently with cholestyramine. 7.6 Acetylsalicylic Acid Acetylsalicylic acid may reduce the efficacy of spironolactone. Therefore, when spironolactone tablets and acetylsalicylic acid are used concomitantly, spironolactone tablets may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained [ see Clinical Pharmacology (12.3 ) ] .

7 DRUG INTERACTIONS • Agents increasing serum potassium: Concomitant administration can lead to hyperkalemia ( 5.1 , 7.1 ). • Lithium: Increased risk of lithium toxicity ( 7.2 ). • NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of ALDACTONE ( 7.3 ). • Digoxin: ALDACTONE can interfere with radioimmunologic assays of digoxin exposure ( 7.4 ). • Cholestyramine: Hyperkalemic metabolic acidosis has been reported with concomitant use ( 7.5 ). • Acetylsalicylic Acid (ASA): ASA may reduce the efficacy of ALDACTONE ( 7.6 ). • Abiraterone: May increase prostate-specific antigen (PSA) levels ( 7.7 ). • Mitotane: Avoid concomitant use of ALDACTONE and mitotane ( 7.8 ). 7.1 Drugs and Supplements Increasing Serum Potassium Concomitant administration of ALDACTONE with potassium supplementation or drugs that can increase potassium may lead to severe hyperkalemia. In general, discontinue potassium supplementation in heart failure patients who start ALDACTONE [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3) ] . Check serum potassium levels when ACE inhibitor or ARB therapy is altered in patients receiving ALDACTONE. Examples of drugs that can increase potassium include: • ACE inhibitors • angiotensin receptor blockers • non-steroidal anti-inflammatory drugs (NSAIDs) • heparin and low molecular weight heparin • trimethoprim 7.2 Lithium Like other diuretics, ALDACTONE reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity. Monitor lithium levels periodically when ALDACTONE is coadministered [see Clinical Pharmacology (12.3) ] . 7.3 Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of diuretics. Therefore, when ALDACTONE and NSAIDs are used concomitantly, monitor closely to determine if the desired effect of the diuretic is obtained [see Clinical Pharmacology (12.3) ] . 7.4 Digoxin Spironolactone and its metabolites interfere with radioimmunoassays for digoxin and increase the apparent exposure to digoxin. It is unknown to what extent, if any, spironolactone may increase actual digoxin exposure. In patients taking concomitant digoxin, use an assay that does not interact with spironolactone. 7.5 Cholestyramine Hyperkalemic metabolic acidosis has been reported in patients given ALDACTONE concurrently with cholestyramine. 7.6 Acetylsalicylic Acid Acetylsalicylic acid may reduce the efficacy of spironolactone. Therefore, when ALDACTONE and acetylsalicylic acid are used concomitantly, ALDACTONE may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained [see Clinical Pharmacology (12.3) ] . 7.7 Abiraterone Spironolactone binds to the androgen receptor and may increase prostate-specific antigen (PSA) levels in abiraterone-treated prostate cancer patients. Concomitant use of spironolactone and abiraterone is not recommended. 7.8 Mitotane Avoid concomitant use of ALDACTONE and mitotane. Spironolactone reduces mitotane plasma levels [see Clinical Pharmacology (12.3) ] .