l The drug has various street names including 'Special K', 'ice', 'chalk', 'crank', 'glass' and 'meth'. It is sold as powder, tablets or crystals.

l It is cheap and relatively easy to make, but the process produces acids and acidic gasses that can cause serious burns.

l The substance affects the central nervous system and users experience temporary hyperactivity and a sense of euphoria. Other effects include tremors and increased heart rate, breathing and blood pressure. Facial ulcerations and sores can develop, and teeth can fall out in a condition known as "meth mouth".

l Dangers associated with overdosing include violent behaviour, chronic paranoia, depression, convulsions and damage to the brain, lungs and kidneys.

l The drug was developed early in the 20th century from amphetamine. It was given to soldiers during the Second World War to enable them to stay awake and compulsively focused. Nazi leader Adolf Hitler is believed to have received daily injections of methamphetamine from his personal physician.

l According to the World Health Organisation, it is second only to marijuana as the most widely-abused illicit drug in the world.

l Until the early 1990s, methamphetamine for the US market was made mostly in labs run by drug traffickers in Mexico and California. Since then, authorities have discovered increasing numbers of small-scale methamphetamine labs all over the United States, mostly in rural, suburban, or low-income areas.