Poppers

sildenafil use, tadalafil use, vardenafil use

Concurrent use of alkyl nitrites with any PDE5 inhibitor (sildenafil, tadalafil, vardenafil) is absolutely contraindicated. Both drug classes act on the cGMP pathway at different points — nitrites increase cGMP production, PDE5 inhibitors prevent its breakdown — producing severe, refractory hypotension that may be fatal. Pfizer issued an explicit contraindication at sildenafil's launch in 1998. High real-world prevalence of combined use documented in MSM/HIV+ populations.

severe hypotension, hemodynamic instability, orthostatic hypotension

Individuals with severe hypotension, hemodynamic instability, or conditions causing chronically low blood pressure should not use alkyl nitrites. The acute vasodilatory effect compounds existing circulatory compromise, risking syncope or cardiovascular collapse.

coronary artery disease, heart failure, recent myocardial infarction

Individuals with coronary artery disease, heart failure, recent myocardial infarction, or other severe cardiovascular conditions face increased risk from the hemodynamic stress of acute vasodilation and compensatory tachycardia. Ventricular fibrillation has been documented (Gooley et al. 2023) following alkyl nitrite inhalation.

G6PD deficiency

G6PD-deficient individuals face heightened risk from alkyl nitrite-induced methemoglobinemia due to impaired endogenous methemoglobin reduction. The standard treatment (methylene blue) is itself relatively contraindicated in G6PD deficiency because it can precipitate hemolytic crisis, creating a dangerous treatment gap.

anemia, sickle cell disease, chronic hypoxia

Individuals with anemia or any condition reducing oxygen-carrying capacity face increased risk from methemoglobin formation. Even modest methemoglobin elevation that would be asymptomatic in healthy individuals may produce clinically significant hypoxia when baseline hemoglobin or oxygen transport is compromised.

open-angle glaucoma, closed-angle glaucoma

Individuals with open-angle or closed-angle glaucoma should exercise caution. Systemic vasodilation from alkyl nitrites may transiently alter intraocular pressure, though no published studies have directly examined this interaction with recreational poppers use.