The term TYPE OF DRUG can refer to a variety of substances, including barbiturates, HEROIN, and sulfa drugs. Barbiturates are a type of sedative-hypnotic drug that were commonly used in the past to treat anxiety and insomnia, but have largely been replaced by safer alternatives due to their high potential for abuse and overdose. HEROIN is an opioid drug that is highly addictive and illegal in most countries. Sulfa drugs are a type of antibiotic that are used to treat bacterial infections.