oxymorphone hydrochloride

Action

Unknown. Thought to interact with opioid receptor sites primarily in limbic system, thalamus, and spinal cord, blocking pain impulse transmission.

Availability

Injection: 1 mg/ml, 1.5 mg/ml

Tablets: 5 mg, 10 mg

Tablets (extended-release): 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg, 30 mg, 40 mg

Indications and dosages

➣ Moderate to severe pain

Adults: 1 to 1.5 mg I.M. or subcutaneously q 4 to 6 hours p.r.n.; or initially, 0.5 mg I.V., increased cautiously until pain relief is satisfactory

➣ To reduce labor pain

Adults: 0.5 to 1 mg I.M.

➣ Initiation of therapy for moderate to severe acute pain in opioid-naïve patients

Adults: 10 to 20 mg (Opana) P.O. q 4 to 6 hours depending on initial pain intensity. If deemed necessary to initiate therapy at lower dose, start with 5 mg. Adjust dosage based on patient's response to initial dose. Dose can then be adjusted to acceptable level of analgesia taking into account pain intensity and adverse effects experienced. For chronic around-the-clock opioid therapy, give 5 mg (Opana ER) q 12 hours; thereafter, individually adjust dosage, preferably at increments of 5 to 10 mg q 12 hours every 3 to 7 days to level that provides adequate analgesia and minimizes side effects; give under close supervision of prescribing physician.

➣ Moderate to severe acute pain when converting from parenteral to oral form in patients requiring continuous, around-the-clock opioid treatment for extended period

Adults: 10 times patient's total daily parenteral oxymorphone dose as Opana, in four or six equally divided doses (for example, approximately 10 mg Opana may be needed to provide pain relief equivalent to total daily I.M. dose of 4 mg oxymorphone); titrate dosage to optimal pain relief or combine with acetaminophen/nonsteroidal anti-inflammatories for optimal pain relief. Or 10 times patient's total daily parenteral oxymorphone dose as Opana ER, in two equally divided doses (for example, approximately 20 mg Opana ER q 12 hours may be needed to provide pain relief equivalent to total daily parenteral dose of 4 mg oxymorphone.

➣ Moderate to severe acute pain when converting from other oral opioids to Opana or Opana ER

Adults: Refer to published relative potency information, keeping in mind that conversion ratios are only approximate. In general, it's safest to start Opana therapy by administering half of calculated total daily dose of Opana in four to six equally divided doses P.O. q 4 to 6 hours. Or, for patients requiring continuous, around-the-clock opioid treatment for extended period, give Opana ER in two divided doses P.O. q 12 hours. Gradually adjust initial dosage of Opana or Opana ER until adequate pain relief and acceptable adverse effects have been achieved.

➣ Moderate to severe acute pain in opioid-experienced patients when converting from Opana to Opana ER

Adults: Administer half patient's total daily oral Opana dose as Opana ER P.O. q 12 hours.

Dosage adjustments

• Mild hepatic impairment (Opana, Opana ER)

• Severe hepatic impairment (Numorphan)

• Moderate to severe renal impairment (Opana, Opana ER)

• Concurrent use of other CNS depressants (Opana, Opana ER)

• Elderly or debilitated patients

Contraindications

• Hypersensitivity to drug or its components, or morphine analogs

• Any situation in which opioids are contraindicated, such as respiratory depression (in absence of resuscitative equipment or in unmonitored settings) and acute or severe bronchial asthma or hypercarbia

• Pulmonary edema secondary to chemical respiratory irritant (Numorphan)

• Suspected or existing paralytic ileus

• Moderate and severe hepatic impairment (Opana, Opana ER)

Precautions

Use cautiously in:

• head trauma, increased intracranial pressure, severe renal disease, hypothyroidism, adrenal insufficiency, urethral stricture, undiagnosed abdominal pain or prostatic hyperpla-sia, biliary tract disease, pancreatitis, extensive burns, alcoholism

• history of substance abuse

• prolonged or high-dose therapy

• elderly or debilitated patients

• labor and delivery

• pregnant or breastfeeding patients

• Pain in immediate postoperative period (first 12 to 24 hours), or if pain is mild or not expected to persist for extended period (Opana ER)

• Children younger than age 18.

Administration

• Give oral on empty stomach at least 1 hour before or 2 hours after eating.

• Tell patient to swallow extended-release tablets whole and not to break, chew, dissolve, or crush tablets.

• Be aware that extended-release tablets are not for p.r.n. use.

• Be aware that extended-release tablets are indicated only for postoperative use if patient had already been receiving drug before surgery or if postoperative pain is expected to be moderate or severe and persist for extended period.

See Be aware that administration from any source (such as beverages or drugs) may result in increased plasma drug levels and potentially fatal overdose of oxymorphone.

See Keep naloxone available to reverse respiratory depression, if necessary.

• Give I.V. dose by direct injection over 2 to 3 minutes.

Adverse reactions

CNS: somnolence (Opana, Opana ER), sedation, headache, drowsiness, confusion, dysphoria, euphoria, dizziness, hallucinations, lethargy, impaired mental and physical performance, depression, restlessness, insomnia, paradoxical stimulation, seizures

CV: hypotension, orthostatic hypotension, palpitations, bradycardia, tachycardia

EENT: blurred vision, miosis, diplopia, visual disturbances, tinnitus

GI: abdominal distention, flatulence (Opana), abdominal pain, dyspepsia (Opana ER), nausea, vomiting, constipation, biliary tract spasm, cramps, dry mouth, anorexia, paralytic ileus, toxic megacolon

GU: urinary hesitancy or retention, urethral spasm, antidiuretic effect

Respiratory: suppressed cough reflex, hypoxia (Opana), atelectasis, respiratory depression, allergic bronchospastic reaction, allergic laryngeal edema or laryngospasm, apnea

Skin: rash, urticaria, pruritus, facial flushing, diaphoresis

Other: pyrexia (Opana, Opana ER), physical or psychological drug dependence, drug tolerance, allergic reaction, injection site reaction (Numorphan)

Interactions

Drug-drug. Agonist/antagonist analgesia (such as buprenorphine, butorphanol, nalbuphine, or pentazocine): reduced oxymorphone effect; may precipitate withdrawal symptoms (Opana, Opana ER)

Anticholinergics: increased risk of urinary retention or severe constipation

Antihistamines (first-generation), antipsychotics, barbiturates, general anesthetics, MAO inhibitors, sedative-hypnotics, skeletal muscle relaxants, tricyclic antidepressants: increased risk of respiratory depression

Propofol: increased risk of bradycardia (Numorphan)

Drug-diagnostic tests. Amylase, lipase: increased levels

Drug-behaviors. Alcohol use or abuse, opiate abuse: increased risk of respiratory depression

Patient monitoring

See Closely monitor respiratory status. Stay alert for respiratory depression and allergic responses affecting bronchi and larynx.

• Monitor vital signs and ECG.

• With prolonged use, watch for signs and symptoms of drug dependence.

• Assess neurologic status carefully. Institute protective measures as needed.

• Monitor patient receiving Opana or Opana ER for breakthrough pain and adverse reaction (especially severe constipation).

Patient teaching

See Instruct patient to immediately report seizures or difficulty breathing.

• Tell patient to rise slowly when changing position, to avoid dizziness from blood pressure decrease.

• Instruct patient taking Opana or Opana ER to report episodes of breakthrough pain and adverse reactions (especially severe constipation that may lead to paralytic ileus).

See Advise patient not to drink alcohol from any source because doing so may result in fatal overdose.

• Caution patient not to drive or perform other hazardous activities.

• Tell patient not to stop taking drug suddenly after several weeks, because withdrawal symptoms may occur.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.