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Medication News & UpdateThyroid supplements Endocrinologist are concerned with the generic thryoid supplement products opn the market. There are now eight different levothyroxine products on the market. The Endocrine Society, the American Thyroid Association, and the American Association of Clinical Endocrinologists supported tricter standards for bioequivalence between T4(levothyroxine) products at a May hearing with the FDA. The FDA does not currently require or recommned obtaining additional thyroid laboratory testing when sweitching from one generic equivalent product to another if they are AB rated(a rating system for comparison of generic product us=tilized by the healthcare professionals for assessing comparable products). FDA believes that small differences related to potency or performance between products, within products, across doses, or with aging are unimportant clinically. Then again revisit the Celebrex, vioxx, bextra scenarios. Dr. Wartofsky point out that existing standards, appropriate for most drugs, are not so for products such as T4. These drugs have a narrow therapeutic range. FDA standards for T4 bioequivalence allow for variations of up to 9% in bioavailability of active ingredient from the reference product. That range is greater than the therapeutic window for T4, especially in patients with thyroid cancer, children, the elderly, and pregnant women, Wartofsky said. The expert groups of endocrinologist are recommending re-testing patients when the patient is switch from one brand to generic or one generic to another. We concur with the endocrinologist and recommend that when the same product is not always dispensedand the patient is switched brand to generic, generic to brand, generic to generic, the TSH level must be retested. Diabetes
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