Orally active synthetic labelled morphine analog. Analgesic (narcotic).
Controlled substance.
生物学の機能
Levorphanol (Levo-Dromoran) is an L-isomer morphinan
derivative of morphine that is five to seven times
more potent than morphine. It produces all of the side
effects associated with morphine but less nausea. It is
indicated for moderate to severe pain as a preoperative
anxiolytic. It is often used in combination with thiopental
to reduce the latter drug’s anesthetic dose and to decrease
postoperative recovery time. The D-isomer of
levorphanol, dextrorphan, does not possess opioid analgesic
activity but is a useful antitussive.
一般的な説明
Levorphanol tartrate is the levorotatory form of methorphanand is approximately 7.5 times more potent than morphineorally. The loss of the 4,5-epoxide and the 7,8-double bondallows levorphanol greater flexibility and presumable leadsto the increased binding affinity at all opioid receptor subtypescompared with morphine. The plasma half-life of levorphanolis about 6 to 8 hours but displays great interpersonvariability and may increase upon repeated dosing. Theexcretion of levorphanol is dependent on the kidneys, socaution must be used in renally compromised patients. The analgesic effect of levorphanol may not match the longplasma half-life, and patients must be closely monitored fordrug accumulation and respiratory depression. Levorphanolhas strong agonist activity at the μ-,κ-, and δ-opioid receptorsand has also been shown to be a noncompetitive Nmethyl-D-aspartate (NMDA)-receptor antagonist. Thepharmacodynamic properties of levorphanol are sufficientlydifferent to make it an attractive alternate for patients thatreceive inadequate pain relief from morphine. Levorphanolis available as a 2-mg oral tablet (Levo-Dromoran), and a2-mg/mL solution for injection.
