Section 21(1)(d) in The Bihar Narcotic Drugs and Psychotropic Substances Rules, 1985
(d)A licensed chemist shall not serve narcotic drugs more than once on the same prescription unless it bears superscription by the approved practitioner who prescribed it stating that it is to be repeated and the intervals of time after which and the number of times (not exceeding thrice) that it is to be repeated. In the absence of such superscription, the prescription shall be retained by the licensed chemist after it has been served once.