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Cetarin: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Cetarin - General Information

A narcotic analgesic that may be habit-forming. It is nearly as effective orally as by injection.

 

Pharmacology of Cetarin

Cetarin 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. Cetarin is similar to morphine in its actions, however it is up to 8 times more potent than morphine. Cetarin 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.

 

Cetarin for patients

 

Cetarin Interactions

Interactions with Other CNS Agents: Concurrent use of Levo-Dromoran with all central nervous system depressants (eg, alcohol, sedatives, hypnotics, other opioids, general anesthetics, barbiturates, tricyclic antidepressants, phenothiazines, tranquilizers, skeletal muscle relaxants and antihistamines) may result in additive central nervous system depressant effects. Respiratory depression, hypotension, and profound sedation or coma may occur. When such combined therapy is contemplated, the dose of one or both agents should be reduced. Although no interaction between MAO inhibitors and Levo-Dromoran has been observed, it is not recommended for use with MAO inhibitors.

Most cases of serious or fatal adverse events involving Levo-Dromoran reported to the manufacturer or the FDA have involved either the administration of large initial doses or too frequent doses of the drug to nonopioid tolerant patients, or the simultaneous administration of levorphanol with other drugs affecting respiration. The initial dose of levorphanol should be reduced by approximately 50% or more when it is given to patients along with another drug affecting respiration.

Interactions with Mixed Agonist/Antagonist Opioid Analgesics:   Agonist/antagonist analgesics (eg, pentazocine, nalbuphine, butorphanol, dezocine and buprenorphine) should NOT be administered to a patient who has received or is receiving a course of therapy with a pure agonist opioid analgesic such as Levo-Dromoran. In opioid-dependent patients, mixed agonist/antagonist analgesics may precipitate withdrawal symptoms.

 

Cetarin Contraindications

Levo-Dromoran is contraindicated in patients hypersensitive to levorphanol tartrate.

 

Additional information about Cetarin

Cetarin Indication

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

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.
Drug Interactions
Cimetidine Cimetidine increases the effect of the narcotic
Food Interactions
Take without regard to meals. Avoid alcohol.
Generic Name
Levorphanol
Synonyms
Dea No. 9220; Dea No. 9733; Levorfanol [Inn-Spanish]; Levorfanolo [Dcit]; Levorphanol Dl-Form; Levorphanol Tartrate; Levorphanolum [Inn-Latin]; Methorfinan [Czech]; Methorphinan; Racemethorphanum; Racemorfano [Inn-Spanish]; Levorphanal; Levorphan
Drug Category
Narcotics; Analgesics, Opioid
Drug Type
Small Molecule; Approved
Other Brand Names containing Levorphanol
Antalgin; Aromarone; Cetarin; Dromoran; Lemoran; Levo-Dromoran; Racemic Dromoran;
Absorption
Levorphanol is well absorbed after PO administration with peak plasma concentrations occurring approximately 1 hour after dosing.
Toxicity (Overdose)
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.
Protein Binding
40%
Biotransformation
Levorphanol is extensively metabolized in the liver and is eliminated as the glucuronide metabolite.
Half Life
11-16 hours
Dosage Forms of Cetarin
Injection, solution Subcutaneous
Chemical Formula
C17H23NO
Organisms Affected
Humans and other mammals