levorphanol tartrate

Action

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.

Availability

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.

Dosage adjustment

• Hepatic or renal insufficiency

• Elderly patients

Contraindications

• Hypersensitivity to drug or other opioid agonists

• Bronchial asthma

• Increased intracranial pressure

• Respiratory depression

• Acute alcoholism

Precautions

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

• children.

Administration

See Make sure resuscitation equipment is available before starting therapy.

Adverse reactions

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

Interactions

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

Patient monitoring

• 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.

Patient teaching

See 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.