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Dronabinol

Pronunciation

Pronunciation: droe-NAB-ih-nahl
Class: Antiemetic, Antivertigo agent

Trade Names

Marinol
- Capsules, gelatin 2.5 mg
- Capsules, gelatin 5 mg
- Capsules, gelatin 10 mg

Pharmacology

Principal psychoactive substance derived from cannabis (marijuana); mechanism by which it prevents nausea and vomiting is unknown.

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Pharmacokinetics

Absorption

90% to 95% absorbed. T max approximately 2 to 4 h.

Distribution

10% to 20% reaches systemic circulation. Vd approximately 10 L/kg. Approximately 97% protein bound.

Metabolism

Liver

Extensive first-pass metabolism yielding active and inactive metabolites.

Elimination

Initial t ½ approximately 4 h. Terminal t ½ is 25 to 36 h. Cl is 0.2 L/kg/h.

Feces

Approximately 50% of dose; less than 5% unchanged drug.

Urine

10% to 15%.

Onset

0.5 to 1 h.

Peak

2 to 4 h.

Duration

4 to 6 h (psychoactive effects), 24 h or longer (appetite stimulant).

Indications and Usage

Control of chemotherapy-induced nausea and vomiting unresponsive to other antiemetics; appetite stimulation in AIDS cachexia.

Contraindications

Hypersensitivity to marijuana or sesame oil.

Dosage and Administration

Antiemetic
Adults and Children

PO 5 mg/m 2 1 to 3 h before chemotherapy and every 2 to 4 h after chemotherapy. Can give 4 to 6 doses/day and increase by 2.5 mg/m 2 /dose; do not exceed 15 mg/m 2 /dose.

Appetite Stimulation
Adults

PO 2.5 mg twice daily before lunch and supper. Can give single daily dose of 2.5 mg to patients in whom adverse effects develop. Can increase by 2.5 mg/day; do not exceed 20 mg/day.

Storage/Stability

Refrigerate capsules; do not freeze.

Drug Interactions

Amphetamines, cocaine, sympathomimetics

Hypertension; tachycardia.

CNS depressants

Increased CNS adverse effects.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Tachycardia; hypotension.

CNS

Euphoria; dizziness; paranoid reaction; somnolence; seizures in patients with existing seizure disorders.

Miscellaneous

Tolerance, psychological and physical dependence with chronic use.

Precautions

Monitor

Assess for nausea, vomiting, appetite, bowel sounds, and abdominal pain before and after drug is administered. Monitor BP and pulse rate during therapy, especially in patients with hypotension or cardiac disease. Monitor I&O, hydration, nutritional status, and weight regularly. Assess for signs of withdrawal syndrome.


Pregnancy

Category B .

Lactation

Excreted in breast milk.

Children

Not recommended in children with AIDS cachexia.

Elderly

More sensitive to psychoactive effects.

Drug dependence

Drug has abuse potential.

Overdosage

Symptoms

Drowsiness, euphoria, heightened sensory awareness, altered time perception, reddened conjunctiva, dry mouth, tachycardia (mild intoxication). Memory impairment, depersonalization, mood alteration, urinary retention, reduced bowel motility (moderate intoxication). Decreased motor coordination, lethargy, slurred speech, postural hypotension (severe intoxication). Apprehensive patients may experience panic reactions. Patients with seizure disorder may experience seizures.

Patient Information

  • Instruct patient to take drug exactly as ordered by health care provider.
  • Discuss psychoactive symptoms with patient and family. Symptoms may be minimized by providing quiet, supportive environment.
  • Explain that signs of overdose (eg, mood changes, confusion, hallucinations, depression, nervousness, fast or pounding heartbeat) may occur with increased doses.
  • Instruct patient to make position changes slowly to prevent orthostatic hypotension.
  • Advise patient and family that adult supervision is necessary as patient may experience drowsiness, dizziness, difficulty concentrating, and perceptual and coordination impairment.
  • Instruct patient to avoid intake of alcoholic beverages, barbiturates, and other CNS depressants.
  • Advise patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.

Copyright © 2009 Wolters Kluwer Health.

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