Twenty-eight studies (n=1,016) were included: 18 RCTs; nine open trials; and one compassionate use programme. Eleven of the 28 studies were full text articles and 17 were conference abstracts (including five unpublished pharmaceutical company trials). Quality scores for the 11 full-text articles ranged from 5 to 13 (mean score of 8.3) out of 15. Study numbers ranged from five to 287 (mean number 37).
Twenty-seven studies assessed symptoms: Eighteen showed a statistically significant improvement either from baseline or compared to control; eight studies showed no statistical difference in improvement; and one study showed no improvement. Eleven studies provided quantifiable data with symptom scores improved by an average of 59.4 per cent (±14.5%). Six of nine uncontrolled studies that showed improvement in symptoms compared with baseline exhibited a statistically significant difference; mean improvement was 63.2 per cent (±10.5%).
Thirteen studies compared domperidone with placebo: Four studies used an enrichment process by which only those who responded to domperidone were included in a second phase in which domperidone was compared with placebo; all four showed a statistically significant improvement in the domperidone group. Of the remaining nine studies comparing domperidone with placebo (without enrichment) one study showed significant improvement in the domperidone group.
Four studies compared cisapride with domperidone: One study showed a statistically significant improvement in the domperidone group; two showed no significant difference; and the remaining study showed a significant improvement with a combination of cisapride and domperidone compared with results from either drug alone.
Two studies compared metoclopramide with domperidone: One showed significant improvement in the domperidone group; the other showed no significant differences.
Fifteen studies assessed gastric emptying before and after domperidone. Nine studies showed a statistically significant improvement in emptying compared with baseline; three studies compared domperidone with placebo and showed improvement in gastric emptying in the domperidone group. Four studies compared cisapride with domperidone; one study showed domperidone to be more effective. One study comparing metoclopramide to domperidone favoured domperidone.
All four studies that assessed the impact of domperidone on quality of life for gastroparesis patients showed improvement, but only one study was statistically significant. Four of six studies that investigated the impact of domperidone on hospital admissions showed a statistically significant reduction in admissions, with the frequency of admissions decreased by an average of 73 per cent. Three studies showed non-significant weight gain. Some studies reported prolactin-related adverse events.