Is Stemitil (prochlorperazine) contraindicated for treating vertigo in a lactating mother?

Stemitil (Prochlorperazine) in Lactating Mothers for Vertigo

Stemitil (prochlorperazine) is not absolutely contraindicated during breastfeeding, but it should be used with significant caution due to limited safety data and the FDA warning that phenothiazines are excreted in breast milk. 1

Key Safety Considerations

The FDA drug label explicitly states that phenothiazines are excreted in breast milk and caution should be exercised when prochlorperazine is administered to nursing women. 1 This is not an absolute contraindication, but rather a warning that requires careful risk-benefit assessment.

Critical Points from FDA Labeling:

• Prochlorperazine belongs to the phenothiazine class, and there is evidence that phenothiazines are excreted in breast milk 1
• The drug may cause somnolence, postural hypotension, and motor/sensory instability in the mother, which could affect infant care 1
• Neonates exposed to antipsychotic drugs can experience extrapyramidal symptoms, though this primarily relates to third-trimester pregnancy exposure 1

Safer Alternative Antiemetics for Vertigo

For treating vertigo-associated nausea in lactating mothers, consider these better-studied alternatives:

First-Line Options:

• Metoclopramide: Relative infant dose 4.7–14.3%, milk:plasma ratio 0.5–4.06, half-life 5–6 hours 2

  • Generally considered compatible with breastfeeding when used for nausea 2
  • Well-documented safety profile in lactation 3

• Domperidone: Relative infant dose 0.01–0.35%, milk:plasma ratio 0.25, half-life 7–14 hours 2

  • Extremely low infant exposure due to high plasma protein binding (93%) and favorable milk:plasma ratio 2

Understanding the Safety Metrics:

The Association of Anaesthetists guideline establishes that drugs with relative infant dose <10% are considered preferred options during lactation 2. Both metoclopramide and domperidone meet this criterion, whereas prochlorperazine lacks published pharmacokinetic data for lactation.

Clinical Decision Algorithm

When a lactating mother presents with vertigo requiring antiemetic therapy:

1. First choice: Domperidone (lowest relative infant dose at 0.01–0.35%) 2

2. Second choice: Metoclopramide (relative infant dose 4.7–14.3%, still within acceptable range) 2

3. If prochlorperazine must be used (e.g., other options failed or contraindicated):

   • Use the lowest effective dose 4
   • Limit duration of treatment 4
   • Monitor infant closely for sedation, feeding difficulties, or extrapyramidal symptoms 1
   • Time breastfeeding to avoid peak drug concentrations in milk 4
   • Consider temporary interruption of breastfeeding if high doses or prolonged use is required 1

Important Caveats

The lack of published pharmacokinetic data for prochlorperazine in lactation is itself a red flag - we have no milk:plasma ratio, relative infant dose, or systematic safety studies, unlike the well-characterized alternatives above 2. This absence of data, combined with the FDA's explicit caution, makes prochlorperazine a suboptimal choice when safer alternatives exist 1.

Premature infants and those with metabolic disorders are particularly vulnerable to drug exposure through breast milk and warrant extra caution 5. The general principle is that infant drug exposure is lower through breast milk than through placental passage during pregnancy, but this does not eliminate risk 5.