Drug interactions and Contraindications

Warfarin + NSAIDs

Increased risk of bleeding

Opioids + Benzodiazepines

Respiratory depression, coma, and death

SSRIs + MAOIs

Serotonin syndrome; contraindicated

Nitrates + Sildenafil

Severe hypotension; contraindicated

ACE inhibitors + Potassium supplements

Hyperkalemia

ACE inhibitors + Spironolactone

Hyperkalemia

Warfarin + TMP-SMX

Increased INR and bleeding risk

Warfarin + Vitamin K

Decreased anticoagulant effect

Lithium + NSAIDs

Increased lithium levels and toxicity

Digoxin + Amiodarone

Increased digoxin levels and toxicity

Statins + Gemfibrozil

Increased risk of rhabdomyolysis

MAOIs + Tyramine-rich foods

Hypertensive crisis

Alcohol + Opioids

Respiratory depression and overdose

Alcohol + Benzodiazepines

Increased sedation and respiratory depression

NSAIDs + Kidney disease

Increased risk of acute kidney injury

NSAIDs + Peptic ulcer disease

Increased risk of GI bleeding

ACE inhibitors + Pregnancy

Fetal injury or death

Levothyroxine + Calcium

Decreased absorption; separate by 4 hours

Levothyroxine + Iron

Decreased absorption; separate by 4 hours

Tetracyclines + Dairy

Decreased antibiotic absorption

Ciprofloxacin + Antacids

Decreased antibiotic absorption

Grapefruit juice + Simvastatin

Increased statin levels and muscle toxicity

Metformin + Severe renal impairment

Increased risk of lactic acidosis

Nonselective beta blockers + Asthma

Bronchospasm

Anticholinergics + Narrow-angle glaucoma

Risk of acute angle-closure glaucoma

Biotin + Thyroid laboratory tests

Falsely abnormal results

Heparin + aPTT

Prolonged aPTT

Warfarin + PT/INR

Increased PT/IN