In Japan, the prescription you receive from your doctor is valid only for 4 days.
So please go to any prescription pharmacy and have it filled within 4 days.
Ministry of Health, Labour and Welfare
Most pharmacies are closed on holidays and Sundays. If you need to have your prescription filled on holidays or weekends, please check which pharmacies are open in your neighborhood by calling the Sapporo Pharmacist Association (9 am to 5 pm).
Tel: 0120-33-8931 for Chuo-ku, Kita-ku, Higashi-ku, Nishi-ku, Teine-ku,
Tel: 0120-22-8941 for Shiroishi-ku, Atsubetsu-ku, Toyohira-ku, Kiyota-ku, Minami-ku.
But the service is only in Japanese. So please ask someone who can speak Japanese to help you get the information.
Sapporo Pharmacist Association, Translated by SEMI
Note： You may have to pay for extra charge at a prescription pharmacy on weekends, holidays or after hours. Be sure to check this matter beforehand.