MINNEAPOLIS — Sublingually administered misoprostol was significantly more effective than the drug given orally after mifepristone for medical abortion in a prospective randomized trial, Sheila Raghavan said at the annual meeting of the Association of Reproductive Health Professionals.
“Medical abortion is becoming more popular and is preferred by women because of the ease of administration and convenience,” Ms. Raghavan said. Misoprostol typically has been administered orally or vaginally for abortion, although this use is off-label and, in fact, the labeling for misoprostol carries a boxed warning stating that its use by pregnant women can not only cause abortion but also birth defects and uterine rupture.
Pharmacokinetic studies have shown higher bioavailability and more rapid absorption when given sublingually. Initial investigations into this route of administration used high doses of sublingual misoprostol and found a high—98%—efficacy rate, but also showed a high rate of side effects. For example, in one study comparing sublingual and vaginal misoprostol given in a dose of 800 mcg, 54% of women receiving the sublingual drug experienced nausea, compared with 32% of those receiving the drug vaginally (Hum. Reprod. 2003;18:2315–8).
For investigation of whether a lower dose (400 mcg) of misoprostol given sublingually after 200 mg oral mifepristone would be effective, tolerable, and acceptable to women, 480 women who ranged in age from 18 to 46 years who were presenting for termination of intrauterine pregnancy were enrolled in the study. Gestational ages up to 63 days were permitted. Approximately 55% of the women had had previous abortions. The trial took place in Moldova, said Ms. Raghavan, who is program research coordinator at Gynuity Health Projects, a reproductive health research and technical assistance organization in New York City.
A total of 240 women were randomized to receive the oral drug, and 240 to receive the sublingual drug, at home 24 hours after receiving 200 mg oral mifepristone in the clinic. Two weeks later they were seen for follow-up assessment, at which time success rates of 98.7% and 94% were seen in the sublingual and oral groups respectively, a difference that statistically favored the sublingual route, Ms. Raghavan said. Four cases, all in the oral group, required surgical intervention.
Fever and chills occurred more frequently in the sublingual group, with 28% of patients reporting these side effects, compared with 18% in the oral group. The nausea lasted significantly longer in the oral group, however, and more than 80% of women in both groups reported that the side effects were acceptable or very acceptable. More than 91% of women in both groups reported being satisfied or very satisfied with the procedure, she said.
The study demonstrates that sublingual misoprostol in a dose of 400 mcg given after 200 mg mifepristone is more effective and as acceptable to women as the oral regimen in inducing abortion, she concluded.