The below link is being highlighted for HIV positive individual and healthcare workers. The link provides information on interactions between HIV treatment and other types of medicine.
For patients there may be too much medical jargon but the conclusions on interactions are clearly described. This is especially useful for when in doubt on whether commonly used over the counter medicines, commonly used herbal products or even vitamins, can be harmful if taken with HIV treatment.
Although recreational drug intake is not suggested with or without HIV, the website also lists the possible interactions of HIV treatment with recreational drugs.