The standard dose of Kamagra is 50mg one hour prior to sexual actions. If you are older than age 65 or have a serious kidney or liver disease some doctors will recommend starting with the minimum dose of 25mg. Kamagra should not be taken more than once per day, period and doses should not exceed 100mg. The half-life of Kamagra, the time the drug remains effective after ingestion, is approximately 4 hours.