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Phenothiazine Antiemetic — Hyperemesis Gravidarum

Prochlorperazine (Nausea and Vomiting in Pregnancy)

Brand names: Stemetil, Buccastem

Prochlorperazine is a phenothiazine antiemetic used here for nausea and vomiting in pregnancy, typically as a second-line option after first-line antihistamine antiemetics.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It blocks dopamine D2 receptors in the chemoreceptor trigger zone, suppressing the emetic reflex.

Prescribing in practice

  • Acute dystonic reactions and other extrapyramidal effects can occur, particularly in younger women, and warrant prompt recognition and treatment.
  • It is used when first-line antiemetics such as antihistamines fail to control nausea and vomiting of pregnancy; severe or refractory cases (hyperemesis gravidarum) need assessment for dehydration and ketosis.
  • It is sedating and can cause hypotension, and caution applies where other QT-prolonging or CNS-depressant drugs are co-prescribed.

Monitoring

Monitor for extrapyramidal symptoms, excessive sedation and postural blood pressure, and review hydration and weight in persistent pregnancy-related vomiting.

Counselling the patient

  • Report any muscle stiffness, abnormal eye movements or involuntary spasms of the face or neck straight away.
  • It may make you drowsy, so take care with tasks needing alertness.
  • Seek review if vomiting continues, you cannot keep fluids down, or you pass little urine.

Evidence & guidelines

UK guidance on nausea and vomiting in pregnancy positions phenothiazines such as prochlorperazine among the antiemetic options after first-line agents.

Reference: RCOG Green-top 69 (Hyperemesis Gravidarum 2024); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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