Prophylactic Pregabalin to Decrease Pain During Medication Abortion: A Randomized Controlled Trial

Abstract

Objective: To evaluate whether prophylactic pregabalin reduces pain experienced with medication abortion.

Methods: We conducted a randomized, double-blind, placebo-controlled trial of women initiating medication abortion with mifepristone and buccal misoprostol up to 70 days of gestation. Participants were randomized to 300 mg oral pregabalin or a placebo immediately before misoprostol. The primary outcome was maximum pain on an 11-point numerical rating scale, reported using real-time electronic surveys over 72 hours. Secondary outcomes included pain at each time point, ibuprofen and narcotic use, side effects, and satisfaction. We estimated that 110 women would be required to have 80% power to detect a difference in pain of 1.3 points.

Results: Between June 2015 and October 2016, 241 women were screened and 110 were randomized (56 pregabalin, 54 placebo). Three were lost to follow-up. The primary outcome of mean maximum pain in the pregabalin group was 5.0±2.6 vs 5.5±2.2 in the placebo group (P=.32). Excluding medication taken before the study capsule, ibuprofen was used by 64% (35/55) of the pregabalin group vs 87% (45/52) placebo (P<.01). Narcotics were used by 29% (16/55) of the pregabalin group vs 50% (26/52) placebo (P<.03). More dizziness (P<.001), sleepiness (P<.04), and blurred vision (P<.05) occurred in the pregabalin group. Satisfaction scores for the analgesic regimen were higher in the pregabalin group (very satisfied: 47% vs 22%; P=.006).

Conclusion: Compared with placebo, 300 mg pregabalin coadministered with misoprostol during medication abortion did not significantly decrease maximum pain scores. Women who received pregabalin were less likely to require any ibuprofen or narcotic and were more likely to report higher satisfaction with analgesia, despite an increase in dizziness, sleepiness, and blurred vision.

Clinical trial registration: ClinicalTrials.gov, NCT02782169.

Conflict of interest statement

The other authors did not report any potential conflicts of interest.

Figures

Figure 1

CONSORT flowchart. *Exclusions: Alternative misoprostol regimen (ie. vaginal or rapid interval) (n=22), allergy to analgesia regimen (n=14),

Figure 2

Distribution of maximum pain scores by treatment group. The percentage of participants in each study group reporting each level of maximum pain. P=.64 using the Fisher exact test.

Figure 3

Mean pain scores over time by treatment group. Mean pain scores at each time point over the study period, compared with t-tests. Because pain scores were compared at so many different time points, it is possible that some of the differences may be due to random variation. *P=.04 at time points 0, 4, and 9 hours.