Table 1 Potential drug-drug interactions (PDDIs) and suggested therapeutic management strategies included in fax alert intervention program

Amiodarone + Macrolides (amiodarone + clarithromycin, erythromycin or azithromycin)

• Change antibiotic therapy: Change to non-macrolide or non-quinolone antibiotic

OR

• Monitor: Monitor ECG at baseline and periodically for QTc prolongation; educate patient about signs of symptomatic cardiac arrhythmias

Amiodarone + Quinolones (amiodarone + gemifloxacin, levofloxacin, moxifloxacin, or ofloxacin)

• Change antibiotic therapy: Change to ciprofloxacin, penicillins, cephalosporins; avoid changing to a macrolide (QTc prolongation)

OR

• Monitor: Monitor ECG at baseline and periodically for QTc prolongation; educate patient about signs of symptomatic cardiac arrhythmias

Benzodiazepines + Azole Antifungal Agents (alprazolam, midazolam, or triazolam + itraconazole, ketoconazole, fluconazole, posaconazole, or voriconazole)

• Change benzodiazepine therapy: Change to lorazepam, oxazepam, or temazepam

OR

• Change antifungal therapy: Change to terbinafine

OR

Monitor: Monitor for excessive sedation and prolonged hypnotic effects; counsel patients about these possible adverse effects; benzodiazepine dose reduction may be required

Carbamazepine + Macrolides (carbamazepine + erythromycin or clarithromycin)

• Change antibiotic therapy: Change to azithromycin or a non-macrolide antibiotic, such as 2nd/3rd generation cephalosporins, penicillins

OR

• Monitor: Monitor for changes in carbamazepine concentrations

Ciprofloxacin + Tizanidine

• Change antibiotic therapy: Change to alternative quinolone (e.g., gemifloxacin, levofloxacin, lomefloxacin, moxifloxacin, norfloxacin, ofloxacin) or non-quinolone antibiotic

OR

• Monitor: Monitor for evidence of tizanidine toxicity such as hypotension and excessive CNS depression

Isotretinoin + Tetracycline or Minocycline

Change antibiotic therapy: Change to a non-tetracycline antibiotic (e.g., macrolide, amoxicillin, sulfamethoxazole/ trimethoprim)

OR

• Monitor: Monitor and educate patient about signs and symptoms of pseudotumor cerebri (e.g., papilledema, headache, nausea, vomiting, visual disturbances)

Simvastatin + Amiodarone

• Change statin therapy: Change to fluvastatin, pravastatin, or rosuvastatin

OR

• Monitor: Monitor for unexplained muscle pain, tenderness, or weakness

Statin + Azole Antifungal Agents (atorvastatin, lovastatin, or simvastatin + itraconazole, ketoconazole, posaconazole, voriconazole, or fluconazole)

• Change statin therapy: Change atorvastatin, lovastatin, or simvastatin (when used in combination with itraconazole, ketoconazole, posaconazole, voriconazole, or fluconazole) to pravastatin OR change fluvastatin or rosuvastatin (when used in combination with fluconazole or voriconazole) to pravastatin, atorvastatin, lovastatin, or simvastatin

OR

• Modify: Temporarily stop the statin for short-term azole antifungal therapy or reduce the statin dosage

OR

• Monitor: Monitor for myopathy and possible rhabdomyolysis

Statins + Macrolides (atorvastatin, lovastatin, or simvastatin + erythromycin or clarithromycin)

• Change antibiotic therapy: Change to azithromycin or a non-macrolide antibiotic

OR

• Change statin therapy: Change to fluvastatin, pravastatin, or rosuvastatin

OR

• Temporarily stop the statin for short-term macrolide therapy

OR

• Monitor for signs of myopathy and possible rhabdomyolysis

Theophylline + Quinolones (theophylline + ciprofloxacin or norfloxacin)

• Change antibiotic therapy: Change to alternative quinolone (e.g., gemifloxacin, levofloxacin, lomefloxacin, moxifloxacin, ofloxacin) or non-quinolone antibiotic

OR

• Monitor: Monitor for changes in theophylline concentrations

Warfarin + Azole Antifungal Agents (warfarin + fluconazole, miconazole, or voriconazole)

• Change the antifungal agent: Change to itraconazole, ketoconazole, posaconazole, or terbinafine

OR

• Monitor: Monitor INR and for bleeding

Warfarin + Fibrates (warfarin + fenofibrate or gemfibrozil)

• Change lipid-lowering therapy: Change to pravastatin, fluvastatin, or possibly extended-release niacin or ezetimibe

OR

• Monitor: Monitor the INR and adjust the warfarin dosage as necessary

Warfarin + Statins ( warfarin + fluvastatin, lovastatin, rosuvastatin, or simvastatin)

• Change statin therapy: Change to atorvastatin or pravastatin

OR

• Monitor: Monitor INR and for bleeding