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Pharmacologic class: Opioid agonist-antagonist
Therapeutic class: Opioid analgesic
Controlled substance schedule III
Pregnancy risk category C
Unclear. May bind to opiate receptors in CNS, altering perception of and response to painful stimuli while causing generalized CNS depression. Also has partial antagonist properties, which may lead to opioid withdrawal effects in patients with physical drug dependence.
Injection: 300 mcg (0.3 mg)/ml
Tablets (sublingual): 2 mg, 8 mg
Indications and dosages
➣ Moderate to severe pain
Adults: 0.3 mg I.M. or slow I.V. q 6 hours as needed. Repeat initial dose after 30 to 60 minutes.
Children ages 2 to 12: 2 to 6 mcg (0.002 to 0.006 mg)/kg I.M. or slow I.V. q 4 to 6 hours
➣ Opioid dependence
Adults: 12 to 16 mg/day S.L.
• Elderly patients
• Hypersensitivity to drug
• Elderly patients
• MAO inhibitor use within 14 days
Use cautiously in:
• increased intracranial pressure (ICP); respiratory impairment; severe renal, hepatic, or pulmonary disease; hypothyroidism; adrenal insufficiency; undiagnosed abdominal pain; prostatic hypertrophy; systemic lupus erythematosus; gout; kyphoscoliosis; diabetes mellitus; alcoholism
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 13.
• Mix with lactated Ringer's injection, dextrose 5% in water, or normal saline solution.
☞ Give I.V. dose slowly over no less than 2 minutes. Drug may cause respiratory depression (especially initial dose).
• When giving I.M., rotate injection sites to prevent induration and abscess.
• If patient is immobilized, reposition him frequently and keep head of bed elevated.
CNS: confusion, malaise, hallucinations, dizziness, euphoria, headache, unusual dreams, psychosis, slurred speech, paresthesia, depression, tremor, agitation, seizures, coma, increased ICP
CV: hypertension, hypotension, palpitations, tachycardia, Wenckebach (Mobitz Type 1) block, bradycardia
EENT: blurred vision, diplopia, amblyopia, miosis, conjunctivitis, tinnitus
GI: nausea, vomiting, constipation, flatulence, ileus, dry mouth
GU: urinary retention
Respiratory: hypoventilation, dyspnea, cyanosis, apnea, respiratory depression
Skin: diaphoresis, pruritus
Other: physical or psychological drug dependence, drug tolerance
Drug-drug. Antidepressants, antihistamines, sedative-hypnotics: additive CNS depression
MAO inhibitors: increased CNS and respiratory depression, increased hypotension
Drug-herbs. Chamomile, hops, kava, skullcap, valerian: increased CNS depression
Drug-behaviors. Alcohol use: increased CNS depression
• Check hepatic function before and during therapy.
• Monitor respiratory status throughout therapy. Respiratory rate of 12 breaths/minute or less may warrant withholding dose or decreasing dosage.
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from sudden blood pressure drop.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Advise patient to increase daily fluid intake to help prevent constipation.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above.