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Numorphan: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Numorphan - General Information

An opioid analgesic with actions and uses similar to those of morphine, apart from an absence of cough suppressant activity. It is used in the treatment of moderate to severe pain, including pain in obstetrics. It may also be used as an adjunct to anesthesia. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1092)

 

Pharmacology of Numorphan

Numorphan is a semi-synthetic opioid substitute for morphine. It is a potent analgesic. Opioid analgesics exert their principal pharmacologic effects on the CNS and the gastrointestinal tract. The principal actions of therapeutic value are analgesia and sedation. Opioids produce respiratory depression by direct action on brain stem respiratory centers. The mechanism of respiratory depression involves a reduction in the responsiveness of the brain stem respiratory centers to increases in carbon dioxide tension and to electrical stimulation.

 

Numorphan for patients

 

Numorphan Interactions

The concomitant use of other CNS depressants including sedatives, hypnotics, tranquilizers, general anesthetics, phenothiazines, other opioids, tricyclic antidepressants, monoamine oxidase (MAO) inhibitors, and alcohol may produce additive CNS depressant effects. When such combined therapy is contemplated, the dose of one or both agents should be reduced.

Anticholinergics or other medications with anticholinergic activity when used concurrently with opioid analgesics may result in increased risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.

It has been reported that the incidence of bradycardia was increased when oxymorphone was combined with propofol for induction of anesthesia.

In addition, CNS toxicity has been reported (confusion, disorientation, respiratory depression, apnea, seizures) following coadministration of cimetidine with opioid analgesics; no clear-cut cause and effect relationship was established.

 

Numorphan Contraindications

NUMORPHAN should not be administered to patients who are hypersensitive to oxymorphone hydrochloride or to any of the other ingredients in NUMORPHAN, or hypersensitive to morphine analogs.

NUMORPHAN should not be administered to individuals during an acute asthmatic attack or to patients with severe respiratory depression, upper airway obstruction, or any patient who has or is suspected of having a paralytic ileus. NUMORPHAN should not be used in the treatment of pulmonary edema secondary to a chemical respiratory irritant. Opioid analgesics cause pooling of blood in the extremities by decreasing peripheral vascular resistance. This effect results in decreases in venous return, cardiac work, and pulmonary venous pressure, and blood is shifted from the central to peripheral circulation which would not be beneficial in the treatment of pulmonary edema secondary to a chemical respiratory irritant.

 

Additional information about Numorphan

Numorphan Indication

For the treatment of moderate-to-severe pain

Mechanism Of Action
Numorphan interacts predominantly with the opioid mu-receptor. These mu-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. They are also found on the terminal axons of primary afferents within laminae I and II (substantia gelatinosa) of the spinal cord and in the spinal nucleus of the trigeminal nerve.
Generic Name
Oxymorphone
Synonyms
Dihydrohydroxymorphinone; Dihydroxymorphinone; Oxymorphine; 14-Hydroxydihydromorphinone; Oximorphonum
Drug Category
Narcotics; Adjuvants; Analgesics; Opiate Agonists
Drug Type
Small Molecule; Approved
Other Brand Names containing Oxymorphone
Numorphan; Opana;
Toxicity (Overdose)
Oxymorphone overdosage is characterized by respiratory depression, extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, and sometimes bradycardia and hypotension. In a severe case of overdose, apnea, circulatory collapse, cardiac arrest, and death may occur. Intravenous mouse LD50 is 172 mg/kg.
Biotransformation
Oxymorphone undergoes extensive hepatic metabolism in humans. After a 10 mg oral dose, 49% was excreted over a five-day period in the urine. Of this, 82% was excreted in the first 24 hours after administration. The recovered drug-related products contained the oxymorphone (1.9%), the conjugate of oxymorphone (44.1%), the 6(beta)-carbinol produced by 6-keto reduction of oxymorphone (0.3%), and the conjugates of 6(beta)-carbinol (2.6%) and 6(alpha)-carbinol (0.1%).
Half Life
1.3 (+/-0.7) hours
Dosage Forms of Numorphan
Suppository Rectal
Chemical Formula
C17H19NO4
Organisms Affected
Humans and other mammals