Ondansetron is a 5-HT3 receptor antagonist used to prevent and treat nausea and vomiting.

Applications:

• Prevents nausea and vomiting from chemotherapy, radiation, and surgery.

• Sometimes used for severe morning sickness in pregnancy.

Side Effects:

• Common: headache, constipation, dizziness.

• Serious (rare): QT prolongation, allergic reactions, serotonin syndrome (when combined with other serotonergic drugs).

Doxylamine Succinate + Pyridoxine Hydrochloride is a combination used to treat nausea and vomiting during pregnancy (morning sickness).

Applications:

• First-line treatment for morning sickness in pregnant women.

• Helps reduce nausea and vomiting without harming the fetus.

Side Effects:

• Common: drowsiness, dry mouth, dizziness, and headache.

• Serious (rare): allergic reactions, confusion, and difficulty urinating.

Dimenhydrinate is an antihistamine primarily used to prevent and treat motion sickness and nausea.

Applications:

• Prevents and relieves nausea, vomiting, and dizziness from motion sickness.

• Used for vertigo and inner ear disturbances like Ménière’s disease.

Side Effects:

• Common: drowsiness, dry mouth, dizziness, and blurred vision.

• Serious (rare): confusion (especially in elderly), fast heartbeat, and urinary retention.