Acute Extrapyramidal Side Effects Following Domperidone Intake in a 48-Year-Old Female Patient: The First Genetic Alteration and Drug Interaction Characterized

No Measurable Transfer of Oxytocin-Receptor Agonist Merotocin Detected in Human Breast Milk

Objective: The study aimed to assess the transfer of merotocin from systemic circulation to breast milk in early postpartum women and women with established lactation. Methods: This was a two-part, multicenter, open-label, parallel-group study. Merotocin was administered as a single 90-minute intravenous (iv) infusion mimicking the intranasal pharmacokinetic profile. In Part A, 12 early postpartum women received doses of either 4 μg (n = 6) or 16 μg (n = 6) of merotocin within 4 days of delivery. In Part B, six women with established lactation received 20 μg of merotocin. The total concentration of merotocin in plasma and breast milk and its metabolites excreted in breast milk were measured at various time points. Adverse events (AEs) were also assessed for both parts of the study. Results: In both early postpartum and established lactation groups (mean age, 26.3 years; 83.3% Caucasian), merotocin and its metabolites in breast milk were below the limit of quantification (25.0 pg/mL) at all time points. Sixteen treatment-emergent AEs occurred in early postpartum women only, including seven events of uterine spasm and three of breast engorgement. There was one moderate event, whereas all the other events were considered mild. Conclusion: Merotocin was undetectable in breast milk after single iv administration of up to 20 μg in early postpartum women and women with established lactation.

Drugs in Focus: Domperidone

Domperidone is a peripheral dopamine-2 receptor antagonist with prokinetic and antiemetic properties. Its prokinetic effects are mainly manifest in the upper gastrointestinal (GI) tract. Currently its use is restricted to relief of nausea and vomiting in children older than 12 years for a short period of time. However, among (pediatric) gastroenterologists, domperidone is also used outside its authorized indication ("off label") for treatment of symptoms associated with gastro-esophageal reflux disease, dyspepsia, and gastroparesis. Little is known about its efficacy in the treatment of GI motility disorders in children and controversial data have emerged in the pediatric literature. As its use is off label, appropriate knowledge of its efficacy is helpful to support an "off label/on evidence" prescription. Based on this, the purpose of this review is to summarize all evidence on the efficacy of domperidone for the treatment of GI disorders in infants and children and to report an overview of its pharmacological properties and safety profile.