Siphene contains Clomiphene Citrate which is an ovulation inducer and can be used to treat infertility. Its dose is one tablet 50 mg daiky during first 5 days of periods consecutively in the first month of tretment. In case of no pregnancy, dose is 100 mg in the next cycle for same duration. If you miss a dose of this medicine then it is possible that desired rsults will not achieved in the current cycle. You should inform this to your doctor.