BBC SPORT | Other Sports | Methamphetamine: What is it?

The substance at the centre of Olympic medallist Alain Baxter's failed drug test is not widely available in the United Kingdom.

The Scottish skier tested positive for methamphetamine, an addictive stimulant which affects the central nervous system.

Baxter has maintained his innocence and stressed that he had never knowingly taken any substance to improve his performance.

The class B controlled drug is a synthetic substance closely related to amphetamine.

Amphetamines
The drug was developed from amphetamine
A police expert told BBC News Online Scotland that methamphetamine was very rare in the UK, where it is usually sold as speed. It is also known as "meth" or "crank".

There is another, highly potent variation of the drug - methyl amphetamine hydrochloride.

Known as "ice" on the street, this drug is more common in the Unites States and the Far East.

However, when methamphetamine is sold in Britain it tends to be of very low purity.

The substance is a mood enhancer which gives the user feelings of euphoria and energy, making the person feel more alert and more energetic. It also takes away feelings of hunger.

Odourless drug

However, the drug wears off very quickly, leaving a feeling of lethargy and anxiety.

Methamphetamine can be taken in pill form or by injecting or snorting the substance, while methyl amphetamine hydrochloride can be smoked.

The white, odourless drug can be made with relatively inexpensive over-the-counter ingredients.

Originally used in nasal decongestants and bronchial inhalers, the drug was developed early this century from amphetamine.

In the long-term there are issues around circulatory damage because it does affect your cardiovascular system

Sally Haw
HEBS research specialist

The effects of methamphetamine are far more pronounced than those of amphetamine.

Snorting or oral ingestion produces euphoria - a high but not an intense rush.

Snorting produces effects within three to five minutes and oral ingestion produces effects within 15 to 20 minutes.

However, the short rush can be followed by a state of high agitation which can lead to violent behaviour. The effects can last up to eight hours.

Tolerance for methamphetamine occurs within minutes - meaning that the pleasurable effects disappear even before the drug concentration in the blood falls significantly.

This means that users try to maintain the high by bingeing on the drug.

Loss of sleep

Sally Haw, a research specialist in substance abuse at the Health Education Board Scotland (HEBS), said amphetamines caused an increase in heart rate and blood pressure.

"In the long-term there are issues around circulatory damage because it does affect your cardiovascular system," she said.

"Long-term use can lead to all sorts of problems."

These also include a loss of sleep and a loss of appetite, as well as a generally run-down feeling.

"Prolonged use can lead to the problems of depression and lack of energy," she added.