Any use of them at all is a form of drug abuse . Often legitimate drugs are abused by people who take more than the recommended dose or take a medication with alcohol or another drug. Drug interactions also produce adverse effects. Therefore, it is important to let your physician know about all the drugs you are taking.
Many drugs are addictive.
A drug dose that is large enough to be toxic is called an overdose. Drug emergencies are not always easy to identify. If you suspect someone has overdosed, or if you suspect someone is experiencing withdrawal, give first aid. Someone who has become addicted to a drug probably won't be able to stop without experiencing withdrawal. Withdrawal is greatly assisted by professional help.