Products
Dronabinol is an anesthetic. The Federal Office of Public Health may grant an exemption for limited medical use. Pharmacies can make dronabinol preparations themselves as an extemporaneous prescription or have them made by contract manufacturing. There are two provisions in the new formulary:
- Oily dronabinol drops 2.5% (NRF 22.8).
- Dronabinol capsules 2.5 mg, 5 mg, 10 mg (NRF 22.7)
In practice, the drops are predominantly used. In the US, dronabinol is commercially available in the form of capsules (Marinol) and as an oral solution (Syndros). In many countries, a cannabis oral spray was approved in 2013. In low concentrations, THC is present in over-the-counter cannabidiol hemp and preparations made from it, such as tinctures.
Structure and properties
Dronabinol is (-)–Δ9-Tetrahydrocannabinol (THC), a natural constituent of the hemp plant L. Dronabinol (C21H30O2, Mr = 314.5 g/mol) is a slightly yellowish, resinous and sticky oil that hardens at cold temperature. Due to its high lipophilicity, it is insoluble in water. Medium-chain triglycerides or sesame oil are usually used to prepare the solutions, and a hard fat or sesame oil is used for the capsules. Sesame oil has the disadvantage of being sensitive to oxidation.
Effects
Dronabinol (ATC A04AD10) has antiemetic, appetite stimulant, analgesic, anti-inflammatory, muscle relaxant, depressant, and psychotropic properties. It is centrally sympathomimetic, which explains the adverse cardiovascular effects. The effects are attributed to binding to cannabinoid receptors (CB) and begin after approximately 30 to 60 minutes. Psychotropic effects last 4 to 6 hours, and appetite stimulation lasts up to 24 hours. By binding to the CB receptors, cannabinoids inhibit the release of neurotransmitters from the presynaptic neuron, among other effects.
Indications
In the United States, dronabinol is approved for the treatment of loss of appetite with weight loss in AIDS patients and as a 2nd-line agent for nausea and vomiting associated with chemotherapy (see also under nabilone). In many countries, it is used primarily for chronic/neuropathic pain and spasticity.
Dosage
According to the drug label. The dose is adjusted on an individual basis. Dronabinol is usually taken perorally. It can also be administered inhalationally in the form of alcoholic solutions, similar to cannabis. The oily drops are odorless and tasteless and are taken with or after a meal on a piece of sugar or bread, on a butter cookie, or in yogurt. It should be noted that they are not water soluble and therefore cannot be diluted with tea or water. To increase appetite, take before meals.
Contraindications
- Hypersensitivity
- Pregnancy and lactation
Caution is advised in psychiatric disorders and cardiovascular diseases. Due to the reduction in responsiveness, participation in road traffic and operation of machinery is not indicated and prohibited by law. For complete precautions, see the drug label.
Interactions
Pharmacodynamic interactions have been described with a number of active ingredients (see SmPC). Central depressant effects may be increased with concomitant administration of alcohol, sedatives, antidepressants, analgesics, and sleeping pills. Anticholinergics may increase tachycardia. Dronabinol has high first-pass metabolism and low bioavailability of 10-20%. It is biotransformed in the liver by CYP450 to the active metabolite 11-OH-dronabinol, among others. After a single dose, dronabinol and its metabolites can still be detected in urine and stool at low concentrations 5 weeks later.
Adverse effects
Adverse effects are dose-dependent, so they are predominantly observed at high doses. They can be attributed, among other things, to the sympathomimetic and psychotropic properties of the substance. The most common possible adverse effects include weakness, palpitations, rapid heartbeat, vasodilatation, flushing, abdominal pain, nausea, and vomiting.Central disorders such as amnesia, nervousness, confusion, paranoia, euphoria, hallucinations, drowsiness, and abnormal thinking are also common. The potential for dependence is considered low for the above indications. However, dronabinol can be addictive and, at high doses, can induce abstinence syndrome, including irritability, sleep disturbances, and restlessness.