dronabinol
Brand: Marinol, Syndros
Beers Criteria
Drug Class: cannabinoid / antiemetic
Drug Family: antiemetic
Subclass: synthetic delta-9-tetrahydrocannabinol
Organ Systems: gastrointestinalcns
Mechanism of Action
Synthetic delta-9-THC that activates CB1 cannabinoid receptors in the vomiting center (dorsal vagal complex), cerebral cortex, and limbic system to suppress CINV. Also stimulates appetite via hypothalamic CB1 receptors, making it useful for anorexia in AIDS patients.
CB1 and CB2 cannabinoid receptors
Indications
- CINV refractory to conventional antiemetics
- anorexia and weight loss in AIDS patients
Contraindications
- hypersensitivity to cannabinoids or sesame oil (capsule formulation)
- history of significant psychiatric disorders
- concurrent alcohol or CNS depressant use
Adverse Effects
Common
- euphoria
- somnolence
- dizziness
- thinking abnormalities
- increased appetite
Serious
- psychiatric symptoms (paranoia, hallucinations, psychosis)
- cardiovascular effects (tachycardia, hypotension)
- dependence and withdrawal
Pharmacokinetics (ADME)
| Absorption | 90–95% absorbed orally; extensive first-pass metabolism; bioavailability ~10–20% |
| Distribution | highly lipophilic; Vd ~10 L/kg; stored in adipose tissue; crosses BBB and placenta |
| Metabolism | extensive hepatic CYP2C9 and CYP3A4 metabolism; active metabolite (11-hydroxy-THC) |
| Excretion | fecal (50%) and renal (20%); may persist weeks due to adipose sequestration |
| Half-life | 25–36 hours (terminal); active metabolite: 4–5 days |
| Onset | 30–60 minutes |
| Peak | 2–4 hours |
| Duration | 4–6 hours (psychoactive); 24 hours (appetite effect) |
| Protein Binding | 97% |
| Vd | 10 L/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| CNS depressants | additive CNS depression, sedation | major |
| anticholinergic agents | additive anticholinergic effects (tachycardia) | moderate |
| CYP2C9 inhibitors | increased dronabinol exposure | moderate |
Nursing Considerations
- Administer 1–3 hours before chemotherapy and continue every 2–4 hours after for CINV; for appetite stimulation, give before meals.
- Assess psychiatric history before initiation; avoid in patients with schizophrenia or other psychotic disorders.
- Implement fall precautions due to dizziness, somnolence, and potential disorientation.
- Warn patients and caregivers about mood changes, paranoia, and judgment impairment; advise against operating machinery.
Clinical Pearls
- Dronabinol is classified as a Schedule III controlled substance; its use for CINV has largely been supplanted by NK1 antagonists and newer combination regimens, but it remains a useful salvage option.
- The prolonged adipose tissue sequestration means psychoactive effects and drug interactions can persist for days to weeks after discontinuation.
Safety Profile
Pregnancy avoid
Lactation contraindicated
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.