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Bind to opioid receptors; specifically, analgesia takes place at the mu receptor.
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Indications: moderate to severe pain.
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Opioid receptor–specific agonists (see below for meperidine, methadone, and tramadol):
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Meperidine (in addition to those listed above for opioid receptor–specific agonists):
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Methadone (in addition to those listed above for opioid receptor–specific agonists):
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Tramadol (in addition to those listed above ...