Pharmacologic class: Synthetic opioid agonist
Therapeutic class: Opioid analgesic
Controlled substance schedule II
Pregnancy risk category C
Inhibits adenylate cyclase, which regulates release of pain neurotransmitters (acetylcholine, dopamine, substance P, and gamma-aminobutyric acid). Also stimulates mu and kappa opioid receptors, altering perception of and emotional response to pain.
Tablets: 2 mg
Indications and dosages
➣ Moderate to severe pain
Adults: 2 mg P.O. q 6 to 8 hours p.r.n., provided patient is assessed for hypoventilation and excessive sedation. If necessary, may increase dosage to up to 3 mg q 6 to 8 hours, after adequate evaluation of patient response. Higher doses may be appropriate in opioid-tolerant patients. Adjust dosage according to patient's severity of pain, age, weight, physical status, underlying diseases, and use of concomitant medications. Total oral daily doses of more than 6 to 12 mg in 24 hours are generally not recommended as starting doses in nonopioid-tolerant patients.
• Hepatic or renal insufficiency
• Elderly patients
• Hypersensitivity to drug or other opioid agonists
• Bronchial asthma
• Increased intracranial pressure
• Respiratory depression
• Acute alcoholism
Use cautiously in:
• renal or hepatic dysfunction, chronic obstructive pulmonary disease, acute abdominal conditions, cardiovascular disease, seizure disorders, cerebral arteriosclerosis, Addison's disease, prostatic hypertrophy, toxic psychosis
• pregnant or breastfeeding patients
☞ Make sure resuscitation equipment is available before starting therapy.
CNS: personality disorders, nervousness, insomnia, hypokinesia, dyskinesia, drowsiness, light-headedness, dizziness, depression, delusions, confusion, amnesia, sedation, euphoria, delirium, mood changes, coma, seizures
CV: palpitations, hypotension, tachycardia, bradycardia, shock, peripheral circulatory collapse, cardiac arrest
EENT: diplopia, abnormal vision
GI: nausea, vomiting, constipation, abdominal pain, dyspepsia, increased colonic motility (in patients with chronic ulcerative colitis), dry mouth
GU: dysuria, urinary retention or hesitancy, ureteral or vesicle sphincter spasms, decreased libido, oliguria
Hepatic: biliary tract spasms, hepatic failure
Respiratory: suppressed cough reflex, hyperventilation, periodic apnea
Skin: urticaria, rash, pruritus, cyanosis, facial flushing
Other: physical or psychological drug dependence
Drug-drug. Alfentanil, fentanyl, sufentanil, other CNS depressants: increased CNS and respiratory depression, increased risk of hypotension
Anticholinergics: increased risk of severe constipation
Antidiarrheals (such as atropine, difenoxin, kaolin, loperamide), antihypertensives: increased risk of hypotension
Buprenorphine, naloxone, naltrexone: decreased levorphanol efficacy
Metoclopramide: antagonism of metoclopramide effects
Neuromuscular blockers: increased risk of prolonged CNS and respiratory depression
Drug-diagnostic tests. Amylase, lipase: increased levels
Drug-behaviors. Alcohol use: increased CNS depression
• Check vital signs and respiratory status, and monitor ECG carefully.
• Evaluate fluid intake and output.
• Assess neurologic status. Institute safety precautions as needed to prevent injury.
• Watch for signs and symptoms of depression.
• Monitor liver and kidney function tests.
☞ Instruct patient or caregiver to report adverse reactions immediately.
• Tell patient or caregiver to use safety measures as needed to prevent injury and to report significant problems.
• Advise patient to avoid alcohol while taking this drug.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.