Cocaine blocks all three monoamine transporters (DAT, NET, SERT) at similar concentrations (KI values 0.2–0.7 μM). Methylphenidate inhibits DAT and NET around 0.1 μM but requires about 1000-fold higher concentration to inhibit SERT. Amphetamine and methamphetamine are most potent at NET (KI 0.07–0.1 μM), 5- to 9-fold less potent at DAT (KI ≈ 0.6 μM), and 200- to 500-fold less potent at SERT (KI 20–40 μM). MDMA shows higher potency at SERT than at DAT. Human and mouse transporters respond similarly to each drug, with KI values within 4-fold. These relative potencies indicate which neurotransmitter systems each stimulant disrupts most.
Ibogaine, an alkaloid from the African shrub Tabernanthe iboga, has psychoactive properties and is being studied as a potential treatment for opioid, stimulant, alcohol, and nicotine addiction. However, its complex interactions with many cellular targets raise significant safety concerns. Beyond neurotoxic effects, ibogaine may harm the heart: several sudden deaths after use have been reported, possibly due to cardiac arrhythmias. In one case, a woman experienced a severely prolonged QT interval and ventricular tachyarrhythmias after taking ibogaine.