Don't use clofazimine with MAC drugs or two antihistamines with protease inhibitors
Clofazimine (trade name Lamprene) is an antibiotic drug approved for treatment of leprosy, sometimes used to treat Mycobacterium avium complex (MAC). MAC is a bacterial infection that can cause serious illness when the CD4 cell count gets low. A recent study (Abbott study M93-069) found that addin clofazimine to a standard treatment combination of clarithromycin (Biaxin) and ethambutol (Myambutol) caused what the Food and Drug Administration (FDA) politely describes as "excessive mortality." This means that PWAs who added clofazimine to their MAC treatment died faster than those who didn't. The actual conclusion from the FDA-analysis of the study was that "clofazimine adds no measurable bacteriological or clinical benefit to clarithromycin and ethambutol and may result in excessive mortality, although the exact mechanism of this is not apparent. It is therefore unwarranted at this time to add clofazimine to clarithromycin and ethambutol for the initial treatment of dMAC [disseminated MAC infection]."
While no official warning has yet been issued by the government, patients in two large MAC treatment trials, CPCRA 027 and ACTG 223, have had clofazimine discontinued. (Earlier in 1996, a federal safety monitoring board stopped another arm of the CPCRA 027 trial, using clarithromycin at 1,000 mg twice daily, which was killing PWAs; a public warning was only issued months later after an ACT UP demonstration.) Unfortunately, current Public Health Service guidelines note that clofazimine is often used as a third drug in MAC treatment. Hopefully these guidelines will be speedily revised.
Protease Inhibitors and Antihistamines
Many people suffer from hay fever and other allergies, and get used to taking antihistamines without thinking about it too much. However, if you're taking any of the protease inhibitors-indinavir (trade name Crixivan), ritonavir (Norvir) or saquinavir (Invirase)-it can be very dangerous to take the antihistamines astemizole or terfanidine, better known by their trade names, Hismanal and Seldane. (As far as is known, other antihistamines are OK.) Protease inhibitors are processed in the body by a pathway in the liver that's also used to break down many other drugs. The protease inhibitors seem to monopolize this pathway, and this can cause other medications to get backed up in the body until they reach dangerous levels. In the case of Hismanal and Seldane, the result can be sedation and even heart failure.
There are also other medications that cannot be taken with protease inhibitors. The best things to do if you're starting a protease inhibitor is a "brown bag" doctor's visit: Throw all your meds in a bag and take them over to your doctor, and then go over the package insert of the protease inhibitor together, making sure none of the meds you are taking is listed as "contraindicated"-medical jargon for "don't take it at the same time!"