| Class | Mechanism | Examples |
| Neuroleptics | Dopamine receptor blockade in lower brainstem (chemoreceptor trigger zone) | - Phenothiazines:
- Chlorpromazine
- Butyrophenones:
- Atypical:
|
| Prokinetic drugs | Peripheral effects to increase peristalsis; metaclopramide also has central dopamine antagonist | |
| 5-HT3 receptor antagonists | Block serotonin receptor (chronic use may cause constipation) | - Palonosetron
- Ondansetron
- Granisetron
- Dolasetron
|
| Anticholinergic drugs | Block acetylcholine release in lower brainstem | - Trimethobenzamide
- Scopolamine
- Promethazine
|
| Antihistamines | Block histamine receptors in lower brainstem | - Meclizine
- Diphenhydramine
- Dimenhydrinate
- Hydroxyzine
|
| Corticosteroids | Multiple effects | |
| Benzodiazepines | Reduce anxiety; direct effect on lower brainstem | |
| Cannabinoids | Binds to cannabinoid receptors to exert direct effect in the lower brainstem | |
