| Heroin | Heroin is commonly called smack and is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine. Generally taken by snorting and injection, heroin is a depressant and slows down body functions. |
| Marijuana | This is isolated from Cannabis sativa. Cannabinoids are a group of chemicals (Figure 8.9), which interact with cannabinoid receptors present principally in the brain. Generally taken by inhalation and oral ingestion, these are known for their effects on cardiovascular system of the body. |
| Cocaine | Coca alkaloid or cocaine is obtained from coca plant Erythroxylum coca. It has a potent stimulating action on central nervous system, producing a sense of euphoria and increased energy. Excessive dosage of cocaine causes hallucinations. It interferes with the transport of the neuro-transmitter dopamine. |
| Morphine | Opioids are the drugs, which bind to specific opioid receptors present in our central nervous system and gastrointestinal tract. Morphine is a very effective sedative and painkiller, and is very useful in patients who have undergone surgery. |