TABLE 2.

Significant rifampin drug interactions with antimicrobial agents^a

Antimicrobial	Interaction(s)	Recommendation	Description	Reference(s)
Antibiotics
Atovaquone	↓Css 54%	Contraindicated	Combination not recommended	6, 104
Clarithromycin	↓CL 90%	No dosage adjustment	Despite reduced levels, still effective with Mycobacterium avium complex treatment	257
Dapsone	↓Css 7- to 10-fold	No dosage adjustment	Effective combination for leprosy	125, 127, 275
Doxycycline	↓Cmax 60-70%	No dosage adjustment	Effective combination for Brucella	54
Linezolid	↓Cmax 41%, ↓Cmin 59%	No dosage adjustment	Gut P glycoprotein metabolism; concern for decreased levels clinically	76, 98
Moxifloxacin	↓AUC 31%, ↓Cmax 32%	No dose adjustment recommended	Reduced glucuronidation; concern for levels of moxifloxacin	184
Metronidazole	↓AUC 33%, ↑CL 44%	No dose adjustment recommended		67
Antifungals
Caspofungin	↓Cmin 31%	Raise caspofungin dose to 70 mg i.v. daily		233
Fluconazole	↓AUC 22%, ↓Cmax 17%, ↑CL 30%	Consider raising fluconazole dose	Would increase dose if used together	192
Itraconazole	Undetectable levels (case report)	Combination not recommended		71
Ketoconazole	↓AUC, ↓Cmax (levels not available)	Combination not recommended		68
Voriconazole	↓AUC 93%, ↓Cmax 96%	Contraindicated		99
Posaconazole	↓AUC, ↓Cmax (levels not available)	Combination not recommended	Warning in package insert, no clinical data	221
HIV medications
NRTI
Zidovudine	↓AUC 47%, ↓Cmax 43%	No dose adjustment recommended		97
NNRTI
Delavirdine	↑CL 27-fold, ↓Cmax 92%, undetectable Cmin	Contraindicated	No longer manufactured	33
Efavirenz	↓AUC 22%, ↓Cmax 24%, ↓Cmin 25%	Consider raising efavirenz dose to 800 mg/day if patient wt >60 kg	Therapeutic drug monitoring may be warranted to avoid toxicity	39, 40, 157, 196
Etravirine	No information available, likely significant ↓AUC and ↓Cmax	Contraindicated		134
Nevirapine	↓AUC 46%, ↓Cmax 42%, ↓Cmin 53%	Contraindicated	Failure of therapy	35, 207
CCR5 antagonist
Maraviroc	Ratio of maraviroc PK parameters with rifampin to those without rifampin was Cmin of 0.22 (90% CI, 0.17-0.28), AUC of 0.368 (90% CI, 0.328-0.413), and Cmax of 0.335 (90% CI, 0.260-0.431)	If used without a strong CYP3A inhibitor, raise maraviroc dose to 600 mg p.i. b.i.d.	Must balance with ritonavir usage	271
		If used with a strong CYP3A inhibitor, 300 mg p.o. b.i.d.
Integrase inhibitor
Raltegravir	↓AUC 40%, ↓Cmax 38%, ↓Cmin 61%	Consider raising raltegravir dose to 800 mg p.o. b.i.d.		52
Protease inhibitors
Amprenavir	↓AUC 82%, ↓Cmax 70%, ↓Cmin 92%	Contraindicated	No longer formulated	203
Atazanavir	↓AUC 53%, ↓Cmax 72%, ↓Cmin 98%	Contraindicated	Ritonavir does not improve levels	2, 111, 161
Darunavir	No information available, likely significant ↓AUC and ↓Cmax	Contraindicated		166
Fosamprenavir	Administration with amprenavir; ↓AUC 82%, ↓Cmax 70%, ↓Cmin 92%	Contraindicated	Prodrug of amprenavir	203
Indinavir	↓AUC 92%, ↓Cmax 87%	Contraindicated		42, 136
Lopinavir-ritonavir	Concentrations of lopinavir, ↓AUC 75%, ↓Cmin 99%	Contraindicated	Ritonavir boosting did not increase levels	166, 209
Nelfinavir	↓AUC 83%, ↓Cmax 76%	Contraindicated		142
Ritonavir	↓AUC 35%, ↓Cmax 25%, ↓Cmin 49%	Contraindicated		166, 209
Saquinavir	↓AUC 70%, ↓Cmax 65%	Contraindicated	Ritonavir boosting did not increase	210
Tipranavir	No information available; likely significant ↓AUC and ↓Cmax	Contraindicated	levels	142

^aAbbreviations: AUC, area under curve; C_max, concentration maximum; C_min, concentration minimum; p.o., oral; CL, clearance; C_ss, steady-state concentration; i.v., intravenous; NRTI, nucleoside reverse transcriptase inhibitor; NNRTI, nonnucleoside reverse transcriptase inhibitor; PK, pharmacokinetic; ↑, increase; ↓, decrease.