Oxymorphone
Oxymorphone is a semi-synthetic opioid analgesic of the morphinan class, structurally related to morphine and heroin.1 First developed in Germany in 1914 and introduced to the American market in 1959,2 it was designed to produce fewer side effects than its predecessors. Oxymorphone is approximately seven times more potent than morphine and is used in the management of moderate to severe pain.34 Notably, it is almost entirely devoid of antitussive properties.
Contents
Dosage & Duration
Dosage
Duration
Subjective Effects
The experience is dominated by classic opioid effects: potent pain relief, sedation, and a warm sense of physical and emotional well-being. As a full mu-opioid agonist considerably more potent than morphine, oxymorphone produces a heavy, relaxed state with pronounced euphoria and mood lift, accompanied by little in the way of sensory alteration. Central nervous system depression scales with dose, progressing from drowsiness toward stupor, with respiratory depression as the principal danger at high doses.
Physical
The body feels heavy, relaxed, and free of pain. Side effects typical of opioids are common, including itchiness, constipation, dry mouth, nausea, dizziness, sweating, and constricted pupils; respiratory depression becomes dangerous at higher doses.
Comfortable
Sedation
Uncomfortable
Cognitive
The headspace is characterized by euphoria, an elevated mood, and a pervasive sense of well-being and contentment, set against a background of increasing sedation and drowsiness.
Emotional
Reagent Testing
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Pharmacology
Pharmacodynamics
Oxymorphone exerts its primary effects through agonism of the μ-opioid receptor.5 It also interacts with the δ-opioid receptor and, to a much lesser extent, the κ-opioid receptor. The nature of its δ-opioid interaction is not fully agreed upon: it has been characterized as antagonism, but has also been described as an activating interaction that may augment its μ-opioid effects. Through μ-opioid receptors on GABAergic interneurons, oxymorphone disinhibits descending pain modulation pathways. It is approximately 10 times more potent than morphine, with 1 mg of oxymorphone hydrochloride considered equivalent to approximately 9.85 mg of morphine sulfate.6
Pharmacokinetics
Oxymorphone undergoes extensive hepatic metabolism.5 Oral bioavailability is notably low at approximately 10%, attributable to substantial first-pass metabolism,5 though co-administration with a large fatty meal can increase it to approximately 40%. The primary metabolic pathway involves conjugation, with the oxymorphone conjugate accounting for the majority of urinary metabolites.6 Additional metabolism occurs via 6-keto reduction, yielding 6β-carbinol and 6α-carbinol derivatives that are subsequently conjugated.6 The elimination half-life is approximately 1.3 hours.6
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
Unsafe
AvoidThere is considerable risk of physical harm when taking these combinations, they should be avoided where possible.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
All other opioids
Harm Potential
Addiction & Dependence
Psychological
Extremely HighOxymorphone is considered extremely addictive with high abuse potential.7 Compulsive redosing is commonly reported, and the drug has been classified as a high-risk opioid due to misuse and abuse concerns.7
Physical
HighChronic use reliably produces physical dependence with withdrawal symptoms occurring upon cessation.7 Neonatal withdrawal syndrome can occur in infants born to mothers who used oxymorphone during pregnancy.7
Toxicity
Heavy doses can cause respiratory depression leading to dangerous or fatal levels of oxygen deprivation; this is the primary mechanism of opioid overdose death and risk increases substantially when combined with other depressants.7
Constipation occurs commonly with use and tolerance to this effect develops particularly slowly compared to other opioid effects.7
Severe overdose may cause bradycardia, hypotension, circulatory collapse, and cardiac arrest.7
Intravenous injection of the reformulated oral tablet has been associated with a rare TTP-like syndrome (thrombotic microangiopathy); this appears specific to abuse of the crush-resistant formulation and does not occur with intended routes of administration.8
History & Culture
Discovery and Development
Oxymorphone was first developed in Germany in 19142 as part of efforts to create opioid analgesics with improved side effect profiles compared to morphine and heroin. The compound exhibits actions and uses similar to morphine, though notably lacks cough suppressant…
Legality
By Country
References
Source Pages
Citations
- (n.d.). OPANA ER (oxymorphone hydrochloride) tablet, film coated, extended release — Prescribing Information. Endo Pharmaceuticals / U.S. Food and Drug Administration. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5ca97412-1594-4a4e-b5e4-8593ffa1b2421
- Vadivelu N, Maria M, Jolly S, Rosenbloom J, Prasad A, & Kaye AD. (2013). Clinical applications of oxymorphone. 9(6), 439–452. https://doi.org/10.5055/jom.2013.0186123
- (September 2025). Oxymorphone — Drug & Chemical Evaluation Section Fact Sheet. Drug Enforcement Administration, Diversion Control Division. https://www.deadiversion.usdoj.gov/drug_chem_info/oxymorphone.pdf12
- (February 2006). Oxymorphone: a review. Supportive Care in Cancer, 14(2), 109–115. https://doi.org/10.1007/s00520-005-0917-11
- (n.d.). OPANA (oxymorphone hydrochloride) tablets prescribing information. Endo Pharmaceuticals / DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=285e60f8-2404-47d0-a171-a4f075d6f418123
- (n.d.). Numorphan (oxymorphone) prescribing information. Endo Pharmaceuticals / RxList. https://www.rxlist.com/numorphan-drug.htm12345678
- (n.d.). Oxymorphone Hydrochloride Tablets — Full Prescribing Information. DailyMed / U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=560e9425-dfcb-4fb4-a759-b1e3f8f40fdb1234567891011
- (January 11, 2013). Thrombotic Thrombocytopenic Purpura (TTP)–Like Illness Associated with Intravenous Opana ER Abuse — Tennessee, 2012. Morbidity and Mortality Weekly Report, 62(1), 1–4. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6201a1.htm123
- U.S. Food and Drug Administration. (8 June 2017). FDA Requests Removal of Opana ER for Risks Related to Abuse. https://www.hiv.gov/blog/fda-requests-removal-opana-er-risks-related-abuse1234
- CDC. (11 January 2013). Thrombotic Thrombocytopenic Purpura (TTP)–Like Illness Associated with Intravenous Opana ER Abuse — Tennessee, 2012. MMWR Morbidity and Mortality Weekly Report, 62(1), 1–4. https://pmc.ncbi.nlm.nih.gov/articles/PMC4604918/1
- CDC. (24 April 2015). Community Outbreak of HIV Infection Linked to Injection Drug Use of Oxymorphone — Indiana, 2015. MMWR Morbidity and Mortality Weekly Report, 64(16). https://pmc.ncbi.nlm.nih.gov/articles/PMC4584812/1
- (July 2016). HIV Infection Linked to Injection Use of Oxymorphone in Indiana, 2014–2015. The New England Journal of Medicine, 375(3), 229–239. https://doi.org/10.1056/nejmoa15151951
- Endo International plc. (6 July 2017). Endo Pharmaceuticals Inc. Announces Withdrawal of Opana ER (July 6, 2017). https://bgamlaw.com/fda-requests-opana-withdrawl/1
- (n.d.). Постановление Правительства РФ от 30.06.1998 N 681 — Перечень наркотических средств (Список I). https://normativ.kontur.ru/document?moduleId=1&documentId=5031951
- (n.d.). Misuse of Drugs Act 1971, Schedule 2, Part I (Class A Drugs). https://www.legislation.gov.uk/ukpga/1971/38/schedule/21
- (n.d.). The Misuse of Drugs Regulations 2001, Schedule 2. https://www.legislation.gov.uk/uksi/2001/3998/schedule/21
- (n.d.). 21 CFR § 1308.12 - Schedule II. https://www.law.cornell.edu/cfr/text/21/1308.121
Further Reading
Automated synthesisInformation aggregated and synthesized using an autonomous workflow built by Josie Kins.
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