Coadministration is contraindicated in the product labels for atazanavir as St John’s wort is expected to substantially decrease atazanavir concentrations, leading to loss of therapeutic effect and possible 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.