General

Pronunciation
droe-NAB-i-nol

Trade Name(s)

• delta-9-tetrahydrocannabinol

• THC

• Marinol

Controlled Substance Schedule
III

Pregnancy Category
Category C

Ther. class.
antiemetics

Pharm. class.
cannabinoids

Indications

• Prevention of serious nausea and vomiting from cancer chemotherapy when other more conventional agents have failed

• Management of anorexia associated with weight loss in patients with AIDS

Action

• Active ingredient in marijuana

• Has a wide variety of CNS effects, including inhibition of the vomiting control mechanism in the medulla oblongata

Therapeutic Effect(s):

• Suppression of nausea and vomiting

• Increased appetite in patients with AIDS

Pharmacokinetics

Absorption: Extensively metabolized following absorption, resulting in poor bioavailability (10–20%)

Distribution: Enters breast milk in high concentrations. Highly lipid-soluble. Persists in tissues for prolonged period of time

Protein Binding: 97%

Metabolism and Excretion: Extensively metabolized; 50% excreted via biliary elimination. At least one metabolite is psychoactive

Half-life: 25–36 hr

TIME/ACTION PROFILE (antiemetic effect)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	2–4 hr	4–6 hr†

†Appetite stimulation lasts 24 hr or longer

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity to dronabinol, marijuana, or sesame oil

• Nausea and vomiting due to any other causes

• Lactation: Lactation

Use Cautiously in:

• Patients with history of substance abuse

• Cardiovascular disease (due to potential adverse effects)

• Mania, depression, or schizophrenia (use may worsen these conditions)

• Patients taking sedatives, hypnotics, or other psychoactive drugs (increased risk of adverse effects)

• Geri: risk of adverse effects

• OB: Safety and efficacy not established

Adverse Reactions/Side Effects

CNS: anxiety, concentration difficulty, confusion, dizziness, drowsiness, mood change, abnormal thinking, depression, disorientation, hallucinations, headache, impaired judgment, memory lapse, paranoia.

EENT: dry mouth.

CV: palpitations, syncope, tachycardia.

GI: abdominal pain, nausea, vomiting.

Derm: facial flushing.

Neuro: ataxia, paresthesia.

Misc: physical dependence, psychological dependence (high doses or prolonged therapy).

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug

• Additive CNS depression with alcohol, antihistamines, barbiturates, benzodiazepines, atropine, scopolamine, lithium, buspirone, muscle relaxants, opioid analgesics, tricyclic antidepressants, and sedative/hypnotics

• Increased risk of tachycardia with amphetamine, atropine, scopolamine, cocaine, sympathomimetics, antihistamines, and tricyclic antidepressants

• May increase blood levels of theophylline

Drug-Natural Products

• Increased risk of tachycardia with caffeine -containing herbs (cola nut, guarana, mate, tea, coffee)

• Concomitant use of kava, valerian, skullcap, chamomile, or hops can increase CNS depression

Route/Dosage

• PO (Adults):
Antiemetic—5 mg/m² 1–3 hr prior to chemotherapy; may repeat every 2–4 hr after chemotherapy to a total of 4–6 doses/day. If 5 mg/m² dose is ineffective and no significant adverse reactions have occurred, dosage may be increased by 2.5 mg/m² to a maximum of 15 mg/m²/dose.
Appetite stimulant—2.5 mg twice daily initially; may be gradually increased as needed (up to 20 mg/day). Reduce dose to 2.5 mg/day in the evening or at bedtime if unable to tolerate 5 mg/day dose.

Availability

• Gelatin capsules: 2.5 mg, 5 mg, 10 mg

Assessment

• Assess nausea, vomiting, appetite, bowel sounds, and abdominal pain prior to and following the administration of this drug

• Monitor hydration, nutritional status, and intake and output. Patients with severe nausea and vomiting may require IV fluids in addition to antiemetics

• Monitor blood pressure and heart rate periodically throughout therapy

• Patients on dronabinol therapy should be monitored closely for side effects because the effects of dronabinol vary with each patient

Potential Nursing Diagnoses

• Risk for deficient fluid volume (Indications)

• Imbalanced nutrition: less than body requirements (Indications)

• Risk for injury (Side Effects)

Implementation

• Dronabinol capsules should be refrigerated (not frozen)

» Physical or psychological dependence may occur with high doses or prolonged therapy, causing a withdrawal syndrome (irritability, restlessness, insomnia, hot flashes, sweating, rhinorrhea, loose stools, hiccups, anorexia) when discontinued. This is unlikely to occur with therapeutic doses and short-term use of dronabinol

• Antiemetic: This drug may be administered prophylactically 1–3 hr prior to chemotherapy and repeated every 2–4 hr after chemotherapy up to 4–6 doses daily. Most patients respond to 5 mg three or four times daily

• Appetite Stimulant: Give 2.5 mg twice daily before lunch and supper initially. Reduce dose to 2.5 mg/day in the evening or at bedtime for patients unable to tolerate 5 mg/day dose. May increase dose to 2.5 mg at lunch and 5 mg before supper or 5 mg at lunch and 5 mg after supper if further therapeutic effect is desired and adverse effects are minimal. Most patients respond to 2.5 mg twice daily dose, but up to 10 mg bid have been tolerated in about 50% of patients. Adverse effects are dose related

Patient/Family Teaching

• Instruct patient to take dronabinol exactly as directed. Take missed doses as soon as possible but not if almost time for next dose; do not double doses. Signs of overdose (mood changes, confusion, hallucinations, depression, nervousness, fast or pounding heartbeat) may occur with increased doses

• Advise patient to call for assistance when ambulating, because this drug may cause dizziness, drowsiness, and impaired judgment and coordination. Avoid driving or other activities requiring alertness until response to the drug is known

• Instruct patient to change positions slowly to minimize orthostatic hypotension

• Caution patient to avoid taking alcohol or other CNS depressants during dronabinol therapy

• Advise patient and family to use general measures to decrease nausea (begin with sips of liquids and small, nongreasy meals; provide oral hygiene; remove noxious stimuli from environment)

Evaluation/Desired Outcomes

• Prevention of and decrease in nausea and vomiting associated with chemotherapy

• Increased or maintained weight in patients with AIDS

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