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What other drugs will affect isoniazid/pyrazinamide/rifampin?

Before taking isoniazid/pyrazinamide/rifampin, tell your doctor if you are taking any of the following drugs:

• antacids. Aluminum salts will decrease the action of isoniazid. Do not take antacids that contain aluminum for 1 to 2 full hours before or after taking a dose of isoniazid.

• allopurinol (Zyloprim). The effects of allopurinol may be decreased by pyrazinamide.

• ketoconazole (Nizoral), itraconazole (Sporanox), or fluconazole (Diflucan). Isoniazid/pyrazinamide/rifampin may decrease the action of the antifungal medicines. Therefore, a fungal infection may not be adequately treated.

• disulfiram (Antabuse). Unusual behavior and coordination difficulties may occur if these medicines are taken together.

Isoniazid may increase the effects of the following medicines:

• warfarin (Coumadin);

• carbamazepine (Tegretol);

• theophylline (Theo-Dur, Theochron, Theolair, Slo-Phyllin, Elixophyllin);

• ethionamide (Trecator-SC);

• cycloserine (Seromycin);

• phenytoin (Dilantin), ethotoin (Peganone), and mephenytoin (Mesantoin).

• meperidine (Demerol); and

• benzodiazepines such as alprazolam (Xanax), diazepam (Valium), lorazepam (Ativan), and temazepam (Restoril).

Before taking isoniazid/pyrazinamide/rifampin, tell your doctor if you are taking any of the medicines listed above.

Rifampin may decrease the effects of the following drugs:

• acetaminophen (Tylenol, others);

• blood thinners such as warfarin (Coumadin);

• barbiturates such as phenobarbital (Luminal, Solfoton), amobarbital (Amytal), secobarbital (Seconal), and butabarbital (Butisol);

• benzodiazepines such as alprazolam (Xanax), diazepam (Valium), and temazepam (Restoril);
• beta-blockers such as atenolol (Tenormin), propranolol (Inderal), and metoprolol (Lopressor);

• heart medicines such as digoxin (Lanoxin), disopyramide (Norpace), quinidine (Quinora, Quinidex, Cardioquin, others), mexiletine (Mexitil), tocainide (Tonocard), verapamil (Calan, Verelan, Isoptin), and enalapril (Vasotec);

• corticosteroids such as prednisone (Deltasone, Orasone, Meticorten), prednisolone (Delta Cortef, Prelone, others), methylprednisolone (Medrol), and betamethasone (Celestone);

• sulfonylureas such as glipizide (Glucotrol), glyburide (Micronase, Diabeta, Glynase), chlorpropamide (Diabinese), tolbutamide (Orinase), and tolazamide (Tolinase);

• HIV and AIDS medicines such as zidovudine (Retrovir), delavirdine (Rescriptor), saquinavir (Invirase), ritonavir (Norvir), indinavir (Crixivan), and nelfinavir (Viracept);

• sulfa medicines such as sulfamethoxazole (Bactrim, Septra, Gantanol, Azo-Gantanol), and sulfisoxazole (Gantrisin, Azo-Gantrisin);

• estrogens such as Premarin, Ogen, Estrace, Menest, Estratab, Ortho-Est, and others;

• oral birth control pills such as Triphasil, Ortho-Novum, Ortho-Cyclen, Ortho-Tri-Cyclen, Ovral, Lo/Ovral, Desogen, Nordette, Levora, Levlen, Tri-Levlen, Nelova, Norinyl, Brevicon, Ovcon, Loestrin, Demulen, and others;

• phenytoin (Dilantin), ethotoin (Peganone), and mephenytoin (Mesantoin);

• theophylline (Theolair, Theo-Dur, Theochron, Theo-Bid, others);

• methadone (Dolophine);

• clofibrate (Atromid-S); and

• cyclosporine (Sandimmune, Neoral).

Pyrazinamide may affect the Acetest and Ketostix urine tests for ketones. This reaction can cause a pink-brown color to appear.

Drugs other than those listed here may also interact with isoniazid/pyrazinamide/rifampin. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.

Where can I get more information?

Your pharmacist has additional information about isoniazid/pyrazinamide/rifampin written for health professionals that you may read.

What does my medication look like?

Isoniazid/pyrazinamide/rifampin is available with a prescription under the brand name Rifater. Other brand or generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you.

• Rifater 50 mg isoniazid/300 mg pyrazinamide/120 mg rifampin--round, light-beige tablets

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.