Is Stemetil (prochlorperazine) safe to use during pregnancy?

Stemetil (Prochlorperazine) Use in Pregnancy

Prochlorperazine can be used during pregnancy for severe, intractable nausea and vomiting, but only after safer first-line options have failed, and it should be reserved for cases where the benefits clearly outweigh the risks. 1, 2

Treatment Algorithm for Nausea and Vomiting in Pregnancy

First-Line Therapies (Use These First)

• Vitamin B6 (pyridoxine) 10-25 mg every 8 hours is the recommended initial pharmacologic treatment 3, 1
• Doxylamine-pyridoxine combination (10 mg/10 mg or 20 mg/20 mg) is FDA-approved and should be used before considering prochlorperazine 3, 1
• H1-receptor antagonists (doxylamine, promethazine, dimenhydrinate) are considered safer alternatives with better safety profiles 3, 1

Second-Line Therapies (If First-Line Fails)

• Metoclopramide has similar efficacy to phenothiazines but with fewer adverse events and no increased risk of congenital defects in a large Danish cohort study of 28,486 exposed pregnancies 1, 4
• Prochlorperazine 5-10 mg every 6-8 hours (or 25 mg suppository every 12 hours) can be considered only for severe cases not responsive to first-line therapies 1

Third-Line Therapies (Severe Cases Requiring Hospitalization)

• Ondansetron may be used on a case-by-case basis, particularly with caution before 10 weeks of pregnancy 1

Safety Profile and Risks

FDA Labeling Warnings

The FDA drug label explicitly states that "safety for the use of prochlorperazine during pregnancy has not been established" and recommends it only for "severe nausea and vomiting that are so serious and intractable that drug intervention is required and potential benefits outweigh possible hazards" 2

Documented Neonatal Risks

• Prolonged jaundice, extrapyramidal signs, hyperreflexia or hyporeflexia have been reported in newborns whose mothers received phenothiazines 2
• Third-trimester exposure carries risk of extrapyramidal and/or withdrawal symptoms in neonates, including agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorders 2
• Some affected neonates have required intensive care unit support and prolonged hospitalization 2

Maternal Adverse Effects

• Central nervous system depression, anticholinergic effects, and drug-induced leukopenia or neutropenia are documented risks 1
• Neuroleptic malignant syndrome, though rare, is a potentially life-threatening complication 1
• Somnolence, postural hypotension, motor and sensory instability may lead to falls and injuries 2

Clinical Decision-Making Framework

When to Consider Prochlorperazine

1. Severity assessment: Use only when nausea and vomiting are severe and intractable 2
2. Treatment failure: First-line therapies (vitamin B6, doxylamine-pyridoxine, H1-antagonists) have been inadequate 1
3. Risk-benefit analysis: The maternal condition poses greater risk than potential fetal effects 2

Contraindications and Precautions

• Avoid in patients with: history of leukopenia, neutropenia, dementia, glaucoma, or seizure disorders 1
• Bone marrow depression or previous hypersensitivity to phenothiazines are contraindications 2
• Monitor closely if treatment extends beyond short-term use 1

Important Clinical Caveats

Timing Considerations

• European guidelines list prochlorperazine as compatible with all trimesters, though this conflicts with FDA caution regarding third-trimester neonatal effects 1, 2
• The second trimester (after 17 weeks) generally carries lower teratogenic risk than the first trimester, though neonatal withdrawal effects remain a concern with late pregnancy use 1

Breastfeeding

• Phenothiazines are excreted in breast milk, and caution should be exercised when administering to nursing women 2

Monitoring Requirements

• Complete fall risk assessments should be performed when initiating treatment and recurrently during therapy 2
• Patients should be cautioned about impaired mental and physical abilities, especially during the first few days of therapy 2