Promethazine Hydrochloride is an antihistamine with antiemetic, sedative, and anticholinergic properties.

Applications:

• Treats nausea, vomiting, and motion sickness.

• Used as a sedative or for allergy symptoms.

• Sometimes used pre/post-surgery for nausea control.

Side Effects:

• Common: drowsiness, dry mouth, dizziness.

• Serious (rare): respiratory depression (especially in children), severe tissue damage if injected improperly.

Fosaprepitant is an antiemetic used to prevent nausea and vomiting caused by chemotherapy.

Applications:

• Prevents acute and delayed nausea/vomiting from highly emetogenic chemotherapy.

• Often used in combination with other antiemetics (like dexamethasone and a 5-HT3 antagonist).

Side Effects:

• Common: fatigue, headache, hiccups, and constipation.

• Serious (rare): infusion site reactions, allergic reactions, liver enzyme elevation.

Brands: Emend (IV).

Domperidone is a dopamine antagonist used to treat nausea, vomiting, and gastrointestinal motility disorders.

Applications:

• Relieves nausea and vomiting.

• Treats gastroparesis by enhancing stomach emptying.

• Sometimes used to increase breast milk production (off-label).

Side Effects:

• Common: dry mouth, abdominal cramps, and headache.

• Serious (rare): heart rhythm disorders, especially in elderly or high doses.

Applications:

Chemotherapy-Induced Nausea/Vomiting (CINV): Prevents acute/delayed nausea from highly emetogenic chemo (e.g., cisplatin).
Moderately Emetogenic Chemo: Used with dexamethasone + 5-HT3 blockers (e.g., ondansetron).
Postoperative Nausea/Vomiting (PONV): Alternative for high-risk surgeries (less common).

Side Effects:

Common: Fatigue, hiccups, constipation, headache, loss of appetite.
Serious (Rare):

• Liver toxicity (elevated LFTs).

• Hypersensitivity (rash, anaphylaxis).

• Drug interactions (CYP3A4 inhibitor—affects warfarin, birth control, some chemo drugs).

Note: Avoid with pimozide (QT prolongation risk). IV form (fosaprepitant) available.