levallorphan

Absorption

Rapidly absorbed.

Toxicity

Oral, rat LD50: 109±4 mg/kg

Indications

For the complete or partial reversal of narcotic depression, including respiratory depression, induced by opioids.

Background

An opioid antagonist with properties similar to those of naloxone; in addition it also possesses some agonist properties. It should be used cautiously; levallorphan reverses severe opioid-induced respiratory depression but may exacerbate respiratory depression such as that induced by alcohol or other non-opioid central depressants. (From Martindale, The Extra Pharmacopoeia, 30th ed, p683)

Definition

ChEBI: Levallorphan is a morphinane alkaloid.

brand name

Lorfan (Roche).

Pharmacokinetics

Levallorphan, an opioid antagonist similar to naloxone, is used to treat drug overdoses. Levallorphan differs from naloxone in that it also possesses some agonist properties. It is an analogue of levelorphanol that counteracts the actions of narcotic analgesics such as morphine. It is used especially in the treatment of respiratory depression due to narcotic overdoses. Levallorphan prevents or reverses the effects of opioids including respiratory depression, sedation and hypotension. Also, it can reverse the psychotomimetic and dysphoric effects of agonist-antagonists such as pentazocine.

Clinical Use

Levallorphan is an opioid antagonist with practically no analgesic action. It has been used as one of the first relative pure antagonists for the treatment of opioid overdosage, to reverse opioid central depression and to antagonize opioidinduced respiratory impairment . The compound is now replaced by naloxone .

Synthesis

Starting material for the levallorphan synthesis is 1-(4-methoxybenzyl)- 1,2,3,4,5,6,7,8-octahydro isoquinoline (1) .

Metabolism

Hepatic.

Purification Methods

It crystallises from aqueous EtOH. It is a narcotic antagonist. [Schneider & Grüssner Helv Chim Acta 34 2211 1951, Hellerbach Helv Chim Acta 39 429 1956.]