Use effectiveness of a spermicidal suppository containing benzalkonium chloride.

A multicentric trial in 9 Spanish Clinics of Family Planning was conducted to evaluate the effectiveness of a vaginal contraceptive Ovule (suppository), containing 18.9 mg of benzalkonium chloride. Gynaecological and cytobacteriological examinations were made to evaluate any possible side-effect. Six-hundred-fifty-three women at risk of unwanted pregnancy accepted the method as the only contraception during 9,517 months. The results are expressed in life-tables (Tietze-Lewit). Net cumulative first segment rate at 12 months were: terminations 27.2; pregnancy 3.7; medical reason 2.3; planned pregnancy 2.8; other personal reasons 18.4. At 24 months the rates were: terminations 34.1; pregnancy 3.7; medical reason 2.6; planned pregnancy 6.5; personal reasons 21.3. Error or failure to use the spermicide resulted in 12 of 23 pregnancies (52%), while in another 4 pregnancies (17%) there were reasonable elements of doubt concerning its correct use. There were no gynaecological or cytological changes. We conclude that this product is a safe and very effective contraceptive if used according to the prescribed instructions and before any sexual encounter.