indication

For the management of moderate to severe pain or as a preoperative medication where an opioid analgesic is appropriate

pharmacology

Levorphanol is a potent synthetic opioid analgesic indicated for the management of moderate to severe pain or as a preoperative medication where an opioid analgesic is appropriate. Levorphanol is similar to morphine in its actions, however it is up to 8 times more potent than morphine. Levorphanol produces a degree of respiratory depression similar to that produced by morphine at equianalgesic doses, and like many mu-opioid drugs, levorphanol produces euphoria or has a positive effect on mood in many individuals.

mechanism of action

Like other mu-agonist opioids it is believed to act at receptors in the periventricular and periaqueductal gray matter in both the brain and spinal cord to alter the transmission and perception of pain.

toxicity

LD₅₀=150 mg/kg (orally in rats). Signs of overdose include nausea, emesis, dizziness, respiratory depression, hypotension, urinary retention, cardiac arrhythmias, allergic reactions, skin rash, and uticaria.

biotransformation

Levorphanol is extensively metabolized in the liver and is eliminated as the glucuronide metabolite.

absorption

Levorphanol is well absorbed after PO administration with peak plasma concentrations occurring approximately 1 hour after dosing.

half life

11-16 hours