Methamphetamine is a new and serious challenge to HIV treatment and prevention, according to an article to be published in the March 15th edition of Clinical Infectious Diseases, which is now available on-line. In the article, the investigators from two HIV treatment centres in New York, where the drug is reported to be widely used by gay men, review published evidence of patterns of methamphetamine use, its potentially harmful effects, and the impact of the drug on the course of HIV infection.
Use of crystal methamphetamine by gay men in the US has been the focus of intensive media interest in recent months. Articles have been appeared in both the mainstream and gay media in the US, highlighting anecdotal reports of the drug’s harmful and addictive properties, its association with risky sexual behaviour, and the ability of the drug to worsen HIV infection.
The Clinical Infectious Diseases article largely reviews evidence from the United States. Although there is concern in some quarters about the use of methamphetamine by gay men in the UK, it is not yet clear how widespread its use is here.
Patterns of use
After cannabis, amphetamine-based drugs including methamphetamine and ecstasy are the most widely used illegal drugs, with approximately 35 million users worldwide. In the US, research has suggested that methamphetamine is particularly popular amongst urban gay men, and is associated with unsafe sex.
A Californian study involving 68 gay men seeking treatment for methamphetamine dependence revealed that 61% were HIV-positive, and that these men were more likely to have injected the drug, to have had a sexually transmitted infection, to have had a larger number of sexual partners and to have had unprotected anal sex.
Use of ecstasy was also found to be associated with an increased risk of unprotected anal sex amongst gay men attending dance clubs in New York, although this study did not find any association between taking methamphetamine and risky sexual activity.
Further evidence suggestive of an association between methamphetamine use and unsafe sex is provided by a study of men infected with syphilis in California. Methamphetamine was widely used by gay men who had the sexually transmitted infection, and the majority of gay men who knew their HIV status were HIV-positive.
Medical problems associated with methamphetamine use
Heart problems, in both the short and long term, have been observed in individuals using methamphetamine. Stroke has been recorded in four men aged 29 – 45 after using the drug.
It is also known that methamphetamine can impair immune responses to infections, and the investigators highlight evidence that the drug impairs CD8 responses, which are vital to fighting primary HIV infection.
Other medical problems reported include gum disease and poisoning, due to the “cutting” of the drug with harmful substances.
The metabolism of methamphetamine and interaction with anti-HIV medication
Methamphetamine is processed by the body using the P450 enzyme, which is also used to metabolise many anti-HIV drugs. A case report from Australia describes the death of an HIV-positive man taking d4T and saquinavir/ritonavir after injecting methamphetamine. Laboratory reports showed evidence of methamphetamine overdose. Two deaths have also been reported in men taking ritonavir-containing HAART regimens who took ecstasy.
Neurotoxicities
Studies in rats have shown that methamphetamine can accumulate in the brain, and impaired motor function and verbal learning skills have been observed in long-term users of the drug. Symptoms were consistent with low-grade Parkinson’s disease in some individuals and did not resolve after use of methamphetamine was stopped.
Synergy with HIV
Some researchers have suggested that the neurotoxic effects of methamphetamine and HIV could act in synergy, increasing the risks and severity of HIV-associated dementia. This is because both HIV and methamphetamine target the dopamine neurotransmitter in the brain.
A study involving FIV, the feline equivalent of HIV, found that methamphetamine increases the ability of FIV to multiply and mutate 15-fold.
Intoxication, withdrawal and tolerance of methamphetamine
Methamphetamine can be smoked, snorted, swallowed, injected, or squirted into the rectum using a syringe after dissolving the drug in water. Effects occur after approximately 20 minutes, but the drug has a long half-life of approximately twelve hours and has been detected in the urine of users up to five days after it was taken.
Although the drug’s pleasant effects can include heightened alertness, euphoria and an increased sense of wellbeing, it can also cause short-term restlessness, irritability, appetite suppression and insomnia. Individuals on “binges” have reported sleeplessness lasting several days leading to drug-induced psychosis.
Prolonged use of the drug can lead to dependence, and withdrawal symptoms are similar to those of major depression.
Psychiatric studies of methamphetamine users
The New York investigators highlight that there are sparse data on the psychiatric symptoms of users. However, a Californian study involving 170 users of the drug found elevated rates of paranoia, depressive symptoms and violent behaviour.
A study, again conducted in California, involving 25 HIV-positive gay men, found that users of the drug reported enhanced sexual enjoyment and escapism as reasons for use, and 50% of men said that using the drug made it easier for them to approach sexual partners and have anonymous sex with multiple partners.
Conclusion
The investigators report that abuse of methamphetamine “poses a serious health risk by predisposing a young section of [gay men] to high-risk sexual behaviour” and that use of the drug has potentially serious medical, neurological and psychiatric implications. They conclude that “methamphetamine abuse represents a new challenge in HIV treatment and prevention”.
Further information on this website
Methamphetamine drastically increases HIV-like virus's ability to replicate in the brain - news story
Methamphetamine use worsens the damage to brain cells in patients with HIV encephalitis - news story
Does methamphetamine affect HIV viral load? - news story
Potential fatal interaction between protease inhibitors and crystal meth - news story
Urbina A et al. Crystal methamphetamine, its analogues, and HIV infection: medical and psychiatric aspects of a new epidemic. Clinical Infectious Diseases 38 (on-line edition), 2004.