Usual Adult Dose for Allergic Rhinitis. 5 to 10 mg orally once a day-Maximum dose: 10 mg/day-Some experts recommend: Patients over 65 years of age should start with 5 mg orally once a day. Each Akineton tablet for oral administration contains 2 mg biperiden hydrochloride. Other ingredients may include corn syrup, lactose, magnesium stearate, potato starch and talc.