Mechanisms and innovations: Pharmacologic mechanisms of crystal meth

Crystal meth is a form of the stimulant drug methamphetamine that, when smoked, can rapidly achieve high concentrations in the brain. Methamphetamine causes the release of the neurotransmitters dopamine, norepinephrine and serotonin and activates the cardiovascular and central nervous systems. The levels of dopamine are low in the brain of some drug users, but whether this represents neuronal loss is uncertain. The areas of the brain involved in methamphetamine addiction are unknown but probably include the dopamine-rich striatum and regions that interact with the striatum. There is no medication approved for the treatment of relapses of methamphetamine addiction; however, potential therapeutic agents targeted to dopamine and nondopamine (e.g., opioid) systems are in clinical testing.Crystal meth (methamphetamine hydrochloride, “ice,” “Tina”) is a smokable, crystalline solid form of methamphetamine, a stimulant that is used for recreational purposes.¹ To a recreational drug user, the advantage of the smokable form of methamphetamine over the oral form is the very rapid and intense “high.” The advantage over the intravenous form, which also has comparably high bioavailability, is the decreased risk and inconvenience associated with the use of needles. The elimination half-life of smoked crystal meth and methamphetamine administered by intranasal or intravenous routes is about 11 hours.¹Apart from the generic risks associated with all forms of methamphetamine, the special public health concern with crystal meth is that this form can cause more overall harm to the public than other forms,^1,2 because it rapidly achieves a high drug concentration with a correspondingly high potential for drug addiction and other toxicities.