The opium poppy is the source of opium, a naturally strong painkilling medication. Various other drugs, called opiates, are derived from this natural source. Opioids, by one definition, are artificial drugs that are manufactured to produce similar biological effects to opiates, but without some unwanted side effects. One difference between an opioid and opiate is therefore that opiates are natural while opioids are synthetic, but both produce similar effects on the body. Sometimes the term opioid is used to refer to both natural and synthetic drugs in this group, or to all chemicals that produce the characteristic biological effect of an opioid and opiate.
A doctor can choose from a range of opiate and opioid medication, along with other types of drugs, when a patient needs a painkiller. Drugs in this group tend to have strong effects on pain, as they alter the way the patient feels pain, rather than reduce the actual pain. They do this through attaching onto molecules that stick out of certain nerve cells called opioid receptors. After attaching, the nerve cell sends messages to the brain that is not an accurate representation of the severity of the pain the body is actually feeling.
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People therefore experience a lessening of pain, which ranges from strong with drugs like morphine, to a weaker effect with a medication like codeine. Other forms of opioid and opiate that produce a strong effect include the anesthetic fentanyl and the illegal street drug heroin. Hydrocodone and oxycodone are some other forms of opioid and opiate that can produce a useful painkilling effect. Tablets, capsules and injections are some of the ways in which opioid drugs can be taken.
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Addiction is a possibility with some opiate and opioid drugs, ranging from abuse of heroin to addiction to prescribed painkillers like meperidine. The drugs produce a dulling of pain, and can at the same time alter the way the brain feels pleasure, to the point where the drug produces an addictive pleasure each time someone takes it. As part of the treatment for this kind of drug addiction, the affected person may actually begin taking another opioid drug like methadone to wean the patient off the initial addiction. Possible side effects of the drugs for people who merely take them as instructed include constipation and sleepiness; those taking too high a dose can potentially suffer a slowing in breathing which may require emergency medical attention.