Coadministration is not recommended in the product labels for nevirapine as St John's wort is expected to substantially decrease nevirapine concentrations and may result in sub-optimal levels. If patient is already taking St John's Wort check nevirapine and if possible viral levels and stop St John's Wort. Nevirapine levels may increase on stopping St John's Wort. The dose of nevirapine may need adjusting. The inducing effect may persist for at least 2 weeks after cessation of treatment with St John's Wort. However, a recent study suggests a low risk of a clinically relevant pharmacokinetic interaction with low-hyperforin formulations (<1 mg/day) of St John’s Wort (hyperforin is the constituent responsible for induction of CYPs and P-gp). Coadministration may be considered with St John’s Wort formulations that clearly state the hyperforin content and which have a total daily hyperforin dose of 1 mg or less.

Coadministration has not been studied. St John’s Wort is an inducer and therefore can reduce cabotegravir exposure. Coadministration of rifampicin (600 mg once daily) and oral cabotegravir (30 mg once daily) decreased cabotegravir AUC by 59% A similar effect is expected with St John’s Wort. Therefore, coadministration is contraindicated with intramuscular cabotegravir due to potential for loss of therapeutic effect and development of resistance. However, a recent study suggests a low risk of a clinically relevant pharmacokinetic interaction with low-hyperforin formulations (<1 mg/day) of St John’s Wort (hyperforin is the constituent responsible for induction of CYPs and P-gp). Coadministration may be considered with St John’s Wort formulations that clearly state the hyperforin content and which have a total daily hyperforin dose of 1 mg or less.

Coadministration has not been studied. Nevirapine, an inducer of CYP3A4, could potentially decrease dolutegravir concentrations. The US Prescribing Information advises that coadministration should be avoided because there are insufficient data to make dosing recommendations. However, the European SPC recommends a dolutegravir dose of 50 mg twice daily with nevirapine, except in the presence of integrase class resistance when alternative combinations that do not include nevirapine should be considered.

Coadministration has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Dolutegravir is mainly glucuronidated by UGT1A1. Cabotegravir does not inhibit or induce UGT enzymes. Note, cabotegravir used as PrEP is not expected to be coadministered with antiretrovirals except in the case of breakthrough infection when an antiretroviral treatment should be initiated. Residual concentrations of cabotegravir may remain in the systemic circulation for prolonged periods (up to 12 months or longer) but are not expected to affect the exposure of antiretroviral drugs initiated after discontinuation of Apretude.

Coadministration has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Note, cabotegravir used as PrEP is not expected to be coadministered with antiretrovirals except in the case of breakthrough infection when an antiretroviral treatment should be initiated. Residual concentrations of cabotegravir may remain in the systemic circulation for prolonged periods (up to 12 months or longer) but are not expected to affect the exposure of antiretroviral drugs initiated after discontinuation of Apretude.

Coadministration has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Note, cabotegravir used as PrEP is not expected to be coadministered with antiretrovirals except in the case of breakthrough infection when an antiretroviral treatment should be initiated. Residual concentrations of cabotegravir may remain in the systemic circulation for prolonged periods (up to 12 months or longer) but are not expected to affect the exposure of antiretroviral drugs initiated after discontinuation of Apretude.

Coadministration has not been studied but based on metabolism and clearance, a clinically significant interaction is unlikely. Data from pharmacokinetic studies suggest that curcuminoids (derived from turmeric extract) are unlikely to affect UGT-mediated metabolism.

Coadministration of nevirapine (200 mg twice daily) with zidovudine (100-200 mg three times daily) decreased zidovudine AUC (28%) and Cmax (30%). There was no significant effect on nevirapine pharmacokinetics. No dosage adjustments are recommended. Granulocytopenia is commonly associated with zidovudine. Haematological parameters should be carefully monitored in patients receiving nevirapine and zidovudine and who have an increased risk of granulocytopenia.

Tenofovir and nevirapine plasma levels remain unchanged when co-administered. Tenofovir-DF and nevirapine can be co-administered without dose adjustments.

Coadministration has not been studied but based on metabolism and clearance, a clinically significant interaction is unlikely. Data from pharmacokinetic studies suggest that turmeric and curcuminoids (derived from turmeric extract) are unlikely to affect CYP3A4-mediated metabolism.