BG C.S.H.B. 2571 75(R)BILL ANALYSIS PUBLIC HEALTH C.S.H.B. 2571 By: Berlanga 4-25-97 Committee Report (Substituted) BACKGROUND The Food and Drug Administration (FDA) has identified approximately 25 Narrow Therapeutic Index (NTI) drugs. Many of these drugs, such as anitconvulsants, antiarrhythmics, and anticoagulants, are used to treat critical medical conditions. These medications are associated with a high risk for toxic reactions and complex drug interactions. They require highly individualized doses, and close supervision by the physician or health care provider to ensure safe use. Based on the FDA's current methodology, two formulations of the same product or two products from different manufacturers are deemed bioequivalent when they are equivalent with respect to the rate and extent of drug absorption. Substitution is made based on an assumption that they provide the same dose-effect. The FDA's current standard states that two formulations whose rate and extent of absorption differ by "-20 percent or +25 percent" or less are generally considered bioequivalent. Product interchange in patients stabilized on a specific brand of a NTI drug requires very close monitoring to ensure there is no loss of efficacy or increased risk of adverse consequences. Current medical practice makes it difficult to coordinate patient monitoring with product substitution, because a patient can be switched from one formulation to another formulation at the pharmacy level without the knowledge of the physician, and possibly without the awareness of the patient. Therefore, it is essential that the physician is confident that different formulations will not introduce clinically significant changes in the patient's response to therapy. PURPOSE CSHB 2571 requires the State Board of Pharmacy, in consultation with the State Board of Medical Examiners, to create a list of narrow therapeutic index drugs subject to this subsection. In addition, CSHB 2571 allows a pharmacist, before refilling a prescription for a NTI drug formulation using a different drug product from the one previously dispensed, to notify the patient and the prescribing practitioner of the substitution. RULEMAKING AUTHORITY It is the committee's opinion that this bill grants additional rulemaking authority to the State Board of Pharmacy, in consultation with the Texas State Board of Medical Examiners, in SECTION 1. [Section 40(m), Texas Pharmacy Act (Article 4542a-1, Vernon's Texas Civil Statutes)]. SECTION BY SECTION ANALYSIS SECTION 1. Amends Section 40, Texas Pharmacy Act (Article 4542a-1, Vernon's Texas Civil Statutes) by adding Subsection (m) as follows: Subsection (m) establishes that drug product selection authorized in this section does not apply to the refill of a prescription for a narrow therapeutic index drug (NTI), except as provided in this subsection. Requires the State Board of Pharmacy, in consultation with the State Board of Medical Examiners, to create rules to establish a list of NTI drugs that are subject to this subsection. Establishes that a prescription for a NTI drug may be refilled using only the same drug product by the same manufacturer that the pharmacist last dispensed under the prescription. Allows a pharmacist who does not have the same drug product by the same manufacturer in stock to dispense a drug product that is generically equivalent if prior to dispensing the medication the pharmacist notifies: (1) the patient, that a substitution of the prescribed drug product has been made; and (2) the prescribing practitioner of the drug product substitution by telephone, facsimile, or mail, at the earliest reasonable time, but not later than 72 hours after dispensing the medication. SECTION 2. Establishes the effective date of this Act to be September 1, 1997. SECTION 3. Emergency Clause. COMPARISON OF ORIGINAL TO SUBSTITUTE CSHB 2571 adds Subsection (m) to Section 40, Texas Pharmacy Act (Article 4542a-1, Vernon's Texas Civil Statutes), and requires the State Board of Pharmacy, in consultation with the Texas State Board of Medical Examiners, to create rules to establish a list of NTI drugs that are subject to this subsection. CSHB 2571 also requires pharmacists to refill a prescription for a narrow therapeutic index drug using only the same drug product by the same manufacturer that the pharmacist last dispensed under the prescription. Makes an exception if the pharmacist does not have the same drug product by the same manufacturer in stock, by allowing the pharmacist to dispense a drug product which is generically equivalent, providing the pharmacist notifies the patient and prescribing practitioner of the drug substitution. HB 2571 amended Section 40(l), Texas Pharmacy Act (Article 4542a-1, Vernon's Texas Civil Statutes), by requiring the written consent from a physician prior to the substitution of a prescribed drug. The changes to HB 2571 were made to address concerns regarding what drugs were considered to be NTI drugs and by whose definition. A provision was also added to address concerns raised by patients, physicians, and pharmacists regarding the interchange of a medication and who is to