Astemizole
Astemizole (marketed under the brand name Hismanal, developmental code R43512) was a second-generation antihistamine drug that has a long duration of action. Astemizole was discovered by Janssen Pharmaceutica in 1977. It has been withdrawn from the market in most countries because of rare but potentially fatal side effects (QTc interval prolongation and related arrhythmias due to hERG channel blockade).
5-HT3 antagonist
There are few side effects related to the use of 5-HT antagonists; the most common are constipation or diarrhea, headache, and dizziness. Unlike antihistamines with antiemetic properties such as cyclizine, 5-HT antagonists do not produce sedation, nor do they cause extrapyramidal effects, as phenothiazines (such as prochlorperazine) sometimes do.