Morphine is often used by heroin addicts as a substitute when heroin is not available. Heroin usually appears as a white, oft-white or brown crystal powder and can be made into a liquid. It can be inhaled or injected under the skin or into a muscle. Most addicts inject heroin directly into a vein for maximum effect. However, some users now smoke heroin to avoid contaminated needles.
Codeine is a white crystal powder or tablet that can be added to liquids.
It also is available in capsule form and as a serum for injection. Codeine is an ingredient in many prescription cough suppressants and minor prescription pain relievers. Less potent and addictive than the other narcotics, codeine is seldom the drug of choice among addicts. Although not an opiate, methadone is a man-made tablet that produces many of the same effects as morphine and heroin. The main purpose of methadone is to act as a substitute-drug in the treatment of heroin addicts.