An Opiate
Heroin is an illegal opiate drug. It is highly addictive as users find that they have a need for persistent, repeated use of the drug (known as craving) and that their attempts to stop using the drug lead to significant and painful physical withdrawal symptoms. Use of heroin causes physical and psychological problems such as shallow breathing, nausea, panic, insomnia, and a need for increasingly higher doses of the drug to get the same effect.

Highly Addictive
Heroin is so addictive because it activates many regions of the brain particularly the regions that are responsible for producing both the pleasurable sensation of "reward" and physical dependence. Together, these actions account for the user's loss of control and the drug's habit-forming action.

Entry into Body
Heroin is a drug that is primarily taken by injection (a shot) with a needle in the vein. This form of use is called Intravenous injection (commonly known as IV injection). This means of drug entry can have grave consequences. Uncertain dosage levels (due to differences in purity), the use of unsterile equipment, contamination of heroin with dotting agents, or the use of heroin in combination with such other drugs as alcohol or cocaine can cause serious health problems such as serum hepatitis, skin abscesses, inflammation of the veins, and cardiac disease (subacute bacterial endocarditis). Of great importance, however, is that the user never knows whether the next dose will be unusually potent, leading to overdose, come, and possible death.

Related Problems
Needle sharing by IV drug users is fast becoming the leading cause of new AIDS cases. The AIDS virus is carried in contaminated blood left in the needle, syringe, or other drug-related implements and is injected into the new user when he or she uses this equipment to inject heroin or other drugs. There is no cure for AIDS and no proven vaccine to prevent it. Heroin use during pregnancy is associated with stillbirths and miscarriages. Babies born addicted to heroin must undergo withdrawal after birth, and these babies show a number of developmental problems.

Signs and Symptoms
The signs and symptoms of heroin use include euphoria, drowsiness, respiratory depression (which can progress until breathing stops), constricted pupils, and nausea. Withdrawal symptoms include watery eyes, runny nose, yawning, loss of appetite, tremors, panic, chills, sweating, nausea, muscle cramps, and insomnia. Elevations in blood pressure, pulse, respiratory rate, and temperature occur as withdrawal progresses. Symptoms of a heroin overdose include shallow breathing, pinpoint pupils, clammy skin, convulsion, and coma.