ATC Group: A04A Antiemetics and antinauseants

Aprepitant is a selective high-affinity antagonist at human substance P neurokinin 1 (NK₁) receptors.

Dolasetron and its active metabolite, hydrodolasetron (MDL 74,156), are selective serotonin 5-HT₃ receptor antagonists not shown to have activity at other known serotonin receptors and with low affinity for dopamine receptors. The serotonin 5-HT₃ receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema.

Dronabinol is an active ingredient of cannabis, which has complex effects on the CNS, including central sympathomimetic activity. Dronabinol exerts its action by activating CB1 and CB2 recepors which makes it a CNS active medicine.

Fosaprepitant is the prodrug of aprepitant and when administered intravenously is converted rapidly to aprepitant. The contribution of fosaprepitant to the overall antiemetic effect has not fully been characterised, but a transient contribution during the initial phase cannot be ruled out.

Granisetron is a potent anti-emetic and highly selective antagonist of 5-hydroxytryptamine (5HT₃ receptors). Pharmacological studies have demonstrated that granisetron is effective against nausea and vomiting as a result of cytostatic therapy.

Nabilone is a synthetic cannabinoid and dibenzopyrane derivative, an analog of dronabinol (also known as tetrahydrocannabinol or THC), the psychoactive ingredient in cannabis with therapeutic use as an antiemetic and as an adjunct analgesic for neuropathic pain. It has been suggested that nabilone is a highly selective and strong agonist for the cannabinoid receptors CB1 and CB2, both of which are coupled to Gi/o proteins. The CB1 receptors are expressed predominantly in central and peripheral neurons and receptor stimulation has been implicated in the reduction of chemotherapy-induced nausea.

Netupitant is a selective antagonist of human substance P/neurokinin 1 (NK₁) receptors. Delayed emesis has been associated with the activation of tachykinin family neurokinin 1 (NK₁) receptors (broadly distributed in the central and peripheral nervous systems) by substance P. As shown in in vitro and in vivo studies, netupitant inhibits substance P mediated responses.

Ondansetron is a potent, highly selective 5HT₃ receptor-antagonist. Its precise mode of action in the control of nausea and vomiting is not known.

Palonosetron is a selective high-affinity receptor antagonist of the 5HT₃ receptor.

Rolapitant is a selective antagonist of human substance P/neurokinin 1 (NK₁) receptors.

Scopolamine is a naturally occurring belladonna alkaloid and has anticholinergic properties. It acts as a competitive antagonist to acetylchloline and other parasympathomimetic agents. Its mechanism of action in the central nervous system in preventing motion sickness has yet to be elucidated. Scopolamine produces classical symptoms of parasympathetic blockade.

Tropisetron is a highly potent and selective competitive antagonist of the 5-HT₃ receptor. Tropisetron selectively blocks the excitation of the presynaptic 5-HT₃ receptors of the peripheral neurons in this reflex, and may exert additional direct actions within the CNS on 5-HT₃ receptors mediating the actions of vagal input to the area postrema.