Complex sentence: Opiates are a class of strong painkillers or analgesic drugs, including those naturally derived from opium, such as morphine and heroin, and opioids are similar synthetic and semi-synthetic drugs such as Percocet, Vicodin, OxyContin and fentanyl.
Split into simpler sentences: Opiates are a class of strong painkillers or analgesic drugs, including those naturally derived from opium, such as morphine and heroin. Opioids are synthetic and semi-synthetic drugs that are similar to opiates and include such drugs as Percocet, Vicodin, OxyContin and fentanyl.