Examples of drugs metabolised by cytochrome P-450 enzymes are:

• Antiarrhythmics (e.g. disopyramide, mexiletine, quinidine, propafenone, tocainide),

• Antiepileptics (e.g. phenytoin),

• Hormone antagonist (antiestrogens e.g. tamoxifen, toremifene, gestinone),

• Antipsychotics (e.g. haloperidol, aripiprazole),

• Anticoagulants (e.g. coumarins),

• Antifungals (e.g. fluconazole, itraconazole, ketoconazole, voriconazole),

• Antivirals (e.g. saquinavir, indinavir, efavirenz, amprenavir, nelfinavir, atazanavir, lopinavir, nevirapine),

• Barbiturates

• Beta-blockers (e.g. bisoprolol, propanolol),

• Anxiolytics and hypnotics (e.g. diazepam, benzodiazepines, zolpicolone, zolpidem),

• Calcium channel blockers (e.g. diltiazem, nifedipine, verapamil, nimodipine, isradipine, nicardipine, nisoldipine),

• Antibacterials (e.g. chloramphenicol, clarithromycin, dapsone, doxycycline, fluoroquinolones, telithromycin),

• Corticosteroids

• Cardiac glycosides (digitoxin, digoxin),

• Clofibrate,

• Systemic hormonal contraceptives

• Oestrogen,

• Antidiabetic (e.g. chlorpropamide, tolbutamide, sulfonylureas, rosiglitazone),

• Immunosuppressive agents (e.g. ciclosporin, sirolimus, tacrolimus)

• Irinotecan,

• Thyroid hormone (e.g. levothyroxine),

• Losartan,

• Analgestics (e.g. methadone, narcotic analgesics),

• Praziquantel,

• Progestogens,

• Quinine,

• Riluzole,

• Selective 5-HT3 receptor antagonists (e.g. ondansetron)

• Statins metabolised by CYP 3A4 (e.g. simvastatin),

• Theophylline,

• Tricyclic antidepressants (e.g. amitriptyline, nortriptyline),

• Cytotoxics (e.g. imatinib),

• Diuretics (e.g. eplerenone)

Patients on oral contraceptives should be advised to use alternative, non-hormonal methods of birth control during Rifadin therapy. Also diabetes may become more difficult to control.

Other Interactions

When rifampicin is given concomitantly with the combination saquinavir/ritonavir, the potential for hepatotoxicity is increased. Therefore, concomitant use of Rifadin with saquinvir/ritonavir is contraindicated (see section 4.3 Contraindications).

When the two drugs were taken concomitantly, decreased concentrations of atovaquone and increased concentrations of rifampicin were observed.

Concurrent use of ketoconazole and rifampicin has resulted in decreased serum concentrations of both drugs.

Concurrent use of rifampicin and enalapril has resulted in decreased concentrations of enalaprilat, the active metabolite of enalapril. Dosage adjustments should be made if indicated by the patient's clinical condition.

Concomitant antacid administration may reduce the absorption of rifampicin. Daily doses of rifampicin should be given at least 1 hour before the ingestion of antacids.

When rifampicin is given concomitantly w