Cannabis

Cannabis or marijuana is an illegal drug derived from the leaves and flowers of the cannabis plant. It is smoked, eaten or drunk in tea. Cannabis can reduce pain symptoms, as well as causing relaxation, sleepiness and light-headedness.

In low doses, cannabis can reduce nausea and stimulate the appetite. However, it can also cause hallucinations, impaired co-ordination, nausea and vomiting, particularly in high doses. In the long-term, some users can become anxious or paranoid, or develop memory problems.

Patients with HIV often use cannabis as an appetite stimulant or to alleviate symptoms of pain. A survey of HIV-positive patients at a large London hospital found that 27% had used cannabis to alleviate symptoms, including reduced appetite, pain, nausea, anxiety and depression. However almost half of the cannabis users reported memory problems.1 Similar rates were seen in a study in Canada.2 However, a study in San Francisco found lower rates of cannabis use, but for similar reasons.3

In contrast to other drugs of abuse, cannabis use may not necessarily reduce adherence. Despite two studies finding a link between cannabis use and worse adherence, a recent study found that relief of moderate or severe nausea with cannabis led to better adherence to HIV treatment.4 5 6 There is no evidence of a link between cannabis use and HIV disease progression.7

Few studies have examined potential interactions between anti-HIV drugs and cannabis. However, there are theoretical interactions between some protease inhibitors and the drug. Further studies are required to determine whether these occur in practice.

An extract of cannabis has been developed into a drug for multiple sclerosis called Sativex. This is taken as a spray under the tongue. An artificial form of cannabis’ active ingredient delta 9-tetrahydrocannabinol (THC) is also licensed, as dronabinol (Marinol). These preparations do not cause the ‘high’ of the illegal drug.

References

  1. Woolridge E et al. Cannabis use in HIV for pain and other medical symptoms. J Pain Symptom Manage 29: 358-367, 2005
  2. Furler MD et al. Medicinal and recreational marijuana use by patients infected with HIV. AIDS Patient Care STDS 18: 215-228, 2004
  3. Prentiss D et al. Patterns of marijuana use among patients with HIV / AIDS followed in a public health care setting. J Acquir Immune Defic Syndr 35: 38-45, 2004
  4. Tucker JS et al. Substance use and mental health correlates of nonadherence to antiretroviral medications in a sample of patients with human immunodeficiency virus infection. Am J Med 114: 573-580, 2003
  5. Kalichman SC et al. HIV treatment adherence and unprotected sex practices in people receiving antiretroviral therapy. Sex Transm Infect 79: 59-61, 2003
  6. de Jong BC et al. Marijuana use and its association with adherence to antiretroviral therapy among HIV-infected persons with moderate to severe nausea. J Acquir Immune Defic Syndr 38: 43-46, 2005
  7. di Franco MJ et al. The lack of association of marijuana and other recreational drugs with progression to AIDS in the San Francisco Men’s Health Study. Ann Epidemiol 6: 283-289, 1996