Methamphetamine

Methamphetamine is an illegal drug that is commonly known as ‘crystal meth’. Although primarily used recreationally, it is occasionally prescribed medically for patients with attention-deficit hyperactivity disorder or narcolepsy. It works by stimulating the release of the brain chemical dopamine, as well as noradrenaline and 5-hydroxytryptamine (serotonin).

Methamphetamine is usually smoked, snorted or injected, although it can also be swallowed or inserted into the anus. It brings about a strong feeling of euphoria in users, along with increased alertness and focus, feelings of power and invulnerability, and a heightened sense of sexual stimulation. It also reduces the appetite and inhibits sleep, as well as increasing heart rate and blood pressure. These effects can last for up to twelve hours.

Users can often take the drug repeatedly over periods of days: the lack of food intake and sleep over these ‘binges’ can have detrimental effects on health, possibly leading to malnutrition, weight loss and irritability, as well as increases susceptibility to infection. After taking the drug, users may also experience paranoia and extreme tiredness.

Methamphetamine is highly addictive. In addition to the psychological and social impact of methamphetamine addiction, heavy users and addicts may experience physical symptoms, notably tooth loss, due to jaw clenching, dry mouth, neglect of personal hygiene and increased intake of sugary drinks.

Methamphetamine use has been linked to an increased risk of transmission of HIV and other sexually transmitted infections, due to its effects of increasing compulsive sexual behaviour, neglect of safer sex practices and the ability to engage in sexual behaviour for extended periods. There are also concerns that users may neglect taking anti-HIV drugs while under the influence of methamphetamine, putting them at risk of drug resistance and treatment failure.¹

While test-tube studies have shown that methamphetamine may be able to accelerate HIV replication, this has not been seen in HIV-positive patients.² However, poor nutrition and lack of sleep may adversely affect disease progression. In addition, there is some evidence that both methamphetamine and HIV can damage brain cells, and that the combined effects of the drug and the virus can lead to neurological problems, including HIV-associated dementia.^{3 4 5}

Methamphetamine levels may be increased by co-administration with protease inhibitors, particularly ritonavir (Norvir), although more research is required. Patients taking protease inhibitors should use methamphetamine with caution.