Table 4. Drug interactions between rifamycin and antiretrovirals.

Rafamycin	Antretroviral agents	Effect on antiretroviral agents and/or concomitant antimycobacterial medication		Dosing recommendations and clinical comments
Rifampin	All PI	↓ PI concentration by >75%		Contraindicated. Consider rifabutin if a rifamycin is indicated.
	BIC	BIC AUC ↓ 75%		Contraindicated.
	EVG/c	Significant ↓ EVG and cobicistat expected		Contraindicated.
	DTG	Rifampin with DTG 50 mg twice daily (Compared to DTG 50 mg twice daily alone):		Patients without suspected or documented INSTI-resistance mutations:
			DTG AUC ↓ 54% and Cmin ↓ 72%	Use DTG 50 mg twice daily suspected or documented INSTI-resistance mutations: Consider an alternative to rifampin, such as rifabutin
		Rifampin with DTG 50 mg twice daily (Compared to DTG 50 mg daily alone):
			DTG AUC ↑ 33% and Cmin ↑ 22%
	RAL	RAL 400 mg: RAL AUC ↓ 40% and Cmin ↓ 61%		Use RAL 800 mg twice daily instead of 400 mg twice daily.
		Rifampin with RAL 800 mg twice daily (Compared to RAL 400 mg twice daily alone):
			RAL AUC ↑ 27% and Cmin ↓ 53%	Do not coadminister RAL 1,200 mg once daily with rifampin.
	TAF	TAF is a P-glycoprotein substrate, its plasma concentrations may be reduced by rifamycin.		Do not coadminister unless benefits outweigh risks.
		TAF with rifampin (Compared with TAF Alone):
			TAF AUC ↓ 55%	Intracellular TFV-DP levels are higher when TAF is co-administered with rifampin compared to when TDF is administered alone, but clinical outcomes have not been studied. If co-administered, monitor virologic response.
			TFV-DP AUC ↓ 36%
	RPV	RPV AUC ↓ 80%		Contraindicated.
	EFV	EFV AUC ↓ 26%		Maintain EFV dose at 600 mg daily and monitor for virologic response.
Rifabutin	DRV/r	Compared with rifabutin (300 mg once daily) Alone, Rifabutin (150 mg every other day) plus DRV/r: ↔ rifabutin AUC and metabolite AUC ↑ 881%		Recommended dose is rifabutin 150 mg once daily.
				Monitor for antimycobacterial activity and consider therapeutic drug monitoring.
	PI/c	↑ rifabutin expected		Do not coadminister.
		↓ cobicistat expected
	BIC	Rifabutin 300 mg once daily:		Do not coadminister.
			BIC AUC ↓ 38% and Cmin ↓ 56%
	DTG	Rifabutin 300 mg once daily:		No dose adjustment needed.
		↔ DTG AUC and Cmin ↓ 30%
	EVG/c	Rifabutin 150 mg every other day with EVG/c once daily (Compared to Rifabutin 300 mg once daily alone):		Do not coadminister.
		↔ rifabutin AUC
		25-O-desacetyl-rifabutin AUC ↑ 625%
		EVG AUC ↓ 21% and Cmin ↓ 67%
	RAL	RAL AUC ↑ 19% and Cmin ↓ 20%		No dose adjustment needed.

AUC, area under the curve; EVG/c, elvitegravir/cobicistat; DTG, dolutegravir; C_min, minimum concentration; INSTI, integrase strand transfer inhibitor; RAL, raltegravir; TAF, tenofovir alafenamide; TFV-DP, tenofovir-diphosphate; RPV, rilpivirine; EFV, efavirenz; DRV/r, ritonavir-boosted darunavir; PI/c, protease inhibitor/cobicistat; BIC, bictegravir; darunavir/ritonavir.