The recreational use of methamphetamine peaked in the 1980s. The December 2, 1989 edition of The Economist described San Diego, California as the "methamphetamine capital of North America."

The kerosene is removed and gas crystals of crude cocaine are left at the bottom of the tank. Typically, the crystals are dissolved in methyl alcohol. They are then recrystallized and dissolved in sulfuric acid, which results in cocaine that is about 60% pure.

Contrary to earlier belief high dose use of cocaine can be detected as long as 10 to 22 days after last use.

A pregnant woman who uses heroin should not attempt to suddenly stop taking the drug. This can put her baby at increased risk of death. She should consult a health care provider or drug treatment center about treatment with a drug called methadone. Although infants born to mothers taking methadone also have withdrawal symptoms, they can be safely treated in the nursery and generally do better than babies born to women who continue to use heroin.