Poppers (active ingredient: amyl nitrite and similar substances) are liquid drugs that are inhaled as a vapor. Poppers are often used during sex because they act as a stimulant.
Poppers intensify sexual pleasure and relax the musculature including the anal sphincter muscle. That is why poppers are often used during sex (primarily during anal sex and fisting).
Poppers increase the heart rate, expand blood vessels and lower blood pressure. Accordingly, poppers can also induce intense dizziness, circulatory problems and collapse, even unconsciousness in extreme cases. Nausea and erectile dysfunction are also possible.
Interactions with HIV medications are unknown at present.
But beware: poppers are extremely dangerous when used in connection with impotence treatments like Viagra®, Cialis®, Levitra® and nitrates (medications for angina pectoris). The substance can induce anywhere from a drop in blood pressure to heart failure. It is life threatening!
Poppers should therefore never be consumed together with the above-mentioned medications.