What antiemetics are used for nausea and vomiting in pregnancy, and in what order?

First-line: antihistamines (cyclizine, promethazine) and pyridoxine (vitamin B6) +/- doxylamine; phenothiazines (prochlorperazine).

Second-line: metoclopramide and ondansetron (used with some caution about early-pregnancy safety) and domperidone. Corticosteroids are reserved for refractory cases.

Clinical relevance. A stepwise antiemetic approach (antihistamines first, then metoclopramide/ondansetron) safely manages NVP/HG.

More Detail

Antiemetics for NVP/hyperemesis

A stepwise approach is used, starting with the safest agents.

First-line

• Antihistamines - cyclizine, promethazine.
• Pyridoxine (vitamin B6), often combined with doxylamine.
• Phenothiazines - prochlorperazine, chlorpromazine.

Second-line

• Metoclopramide (dopamine antagonist; limit duration - extrapyramidal effects).
• Ondansetron (5-HT3 antagonist; effective - used with awareness of debated early-pregnancy safety data, generally after the first trimester or where benefits outweigh).
• Domperidone.

Refractory

• Corticosteroids - reserved for severe, refractory hyperemesis.

Principle

Start with first-line agents; escalate if symptoms persist, alongside rehydration, thiamine and thromboprophylaxis as needed.