Pharmacology · Cannabinoids (medical antiemetics and appetite stimulants)

Dronabinol !

Synthetic THC in capsules. It relieves chemotherapy vomiting when standard drugs fail and stimulates appetite in AIDS, at the cost of psychoactive effects.

Updated 2026-11-01

Class: Cannabinoids (medical antiemetics and appetite stimulants)
Receptor: Cannabinoid receptor 1 (CB1)
ATC code: A04AD10

Also called: Delta-9-tetrahydrocannabinol (THC)

Cannabinoid receptor 1 (CB1)Dronabinol

No structure of dronabinol bound to CB1 exists; the figure shows AM11542, a synthetic analogue built on the same THC scaffold, in the orthosteric pocket of the human CB1 receptor.

Target in 3D: Cannabinoid receptor 1 (CB1). PDB structure 5XRA (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Dronabinol is chemically synthesised delta-9-tetrahydrocannabinol, the main psychoactive compound of cannabis. It is a low-efficacy agonist of CB1 and CB2 receptors. Activation of CB1 receptors in the brainstem and hypothalamus reduces nausea and vomiting and increases appetite; the same receptors in the cortex and limbic system produce euphoria, sedation, altered perception and, at times, anxiety or paranoia. It also has central sympathomimetic effects (tachycardia).

Dronabinol (synthetic THC) is absorbed and reaches the brain
It activates CB1 receptors in the brainstem and hypothalamus
Nausea falls and appetite rises
CB1 in the cortex and limbic system causes euphoria and sedation

Pharmacokinetics

Absorption: 90–95% absorbed by mouth, but only 10–20% reaches the circulation because of first-pass metabolism and high lipid solubility.
Distribution: Very large volume of distribution (fat-soluble); about 97% protein-bound together with its metabolites.
Metabolism: Extensive first-pass metabolism in the liver, mainly by hydroxylation (CYP2C9 and CYP3A4 involved); the main metabolite, 11-hydroxy-THC, is also active.
Half-life: Initial half-life about 4 hours and terminal half-life 25–36 hours.
Onset and duration: Acts within 0.5–1 hour; psychoactive effects last 4–6 hours, while the appetite effect may last 24 hours.

Indications

Anorexia with weight loss in adults with AIDS. HIV infection and AIDS →
Nausea and vomiting from cancer chemotherapy that has not responded to conventional antiemetics.

Adverse effects

Common

Dizziness and drowsiness
Euphoria, abnormal thinking and paranoid reactions
Abdominal pain, nausea and vomiting
Tachycardia

Contraindications

Hypersensitivity to dronabinol or to sesame oil (in the capsules)

Key interactions

Alcohol, benzodiazepines, barbiturates and other CNS depressants: Additive sedation and CNS depression.
Amphetamines, sympathomimetics, atropine, antihistamines, tricyclic antidepressants and other anticholinergics: Additive tachycardia, hypertension and drowsiness.
CYP2C9 and CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin, ritonavir, grapefruit juice) or inducers: Inhibitors raise dronabinol levels and adverse effects; inducers lower its effect.
Highly protein-bound drugs with a narrow margin (warfarin, ciclosporin, amphotericin B): Possible displacement from plasma proteins; their effects are monitored.

What is monitored

Mood, thinking and psychiatric symptoms, especially at the start and after dose increases
Blood pressure, heart rate and fainting in people with heart disease
Signs of misuse
Weight and appetite in AIDS-related weight loss

Administration and safety

Oral capsules (in sesame oil) or oral solution
It is a controlled substance: storage and records follow local rules
Patients do not drive or operate machinery until they know how it affects them

Nursing care

Ask about psychiatric history, seizures, heart disease and past substance use before starting
Check for sesame allergy
Watch for dizziness and falls, especially in older adults
Teach the patient to avoid alcohol and other sedatives and to report mood changes or worsening vomiting

Pregnancy and breastfeeding

It may cause fetal harm and is avoided in pregnancy; cannabis use in pregnancy has been linked to adverse fetal outcomes.

Test yourself

Think of the answer, then tap the question to see it.

What is dronabinol chemically?

Synthetic delta-9-tetrahydrocannabinol (THC), formulated in sesame oil.

Why does only a small fraction of oral dronabinol reach the circulation although it is well absorbed?

Heavy first-pass hepatic metabolism and high lipid solubility.

Which allergy is a contraindication to dronabinol capsules?

Allergy to sesame oil, the vehicle of the capsules.

Which two indications does dronabinol have?

Anorexia with weight loss in AIDS, and chemotherapy-induced nausea and vomiting that does not respond to conventional antiemetics.

Add to my cards (4)

HIV infection and AIDS

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - DRONABINOL capsule (DailyMed (U.S. National Library of Medicine), 2026); Dronabinol: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 26 (McGraw Hill, 2023); RCSB PDB - 5XRA: Crystal structure of the human CB1 in complex with agonist AM11542 (RCSB Protein Data Bank, 2026).

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Representative model, for educational purposes only.