Synphasic tablets in Canadian practice: a phase-IV multicenter study.
The performance of a low-dose triphasic oral contraceptive (OC) in the first four cycles of use was evaluated by 1,326 primary-care physicians and specialists across Canada in a phase-IV postmarketing trial. Data were available from 5,460 women who completed 19,756 cycles of use with Synphasic. The incidence of intermenstrual bleeding characteristically decreased over the four cycles to 10% in women who were first-time users of OCs, to 14% in women who had previously used OCs but had discontinued use until this trial, and to 16% in women who had switched from another OC to Synphasic. The women reported a low incidence of headache, nausea, weight gain, breast complaints, and acne while receiving Synphasic. The results demonstrate good endometrial control with Synphasic and a high level of patient acceptance.