New and old tablets of this popular semaglutide will not have the same effect, warns ISMP Canada

Be careful when filling Rybelsus prescriptions during the switch to its new formulation, says ISMP Canada in its latest safety brief, after medication errors involving the old and new tablets of the semaglutide were reported.In one case, a refill for 7 mg of the original formulation was dispensed using a mix of 3-mg original tablets and 4-mg tablets of the new formulation. Although the strengths appeared to add up to 7 mg, the combination was equivalent to 10 mg of the original formulation.While the error was caught at prescription pickup, ISMP Canada is warning that the old and new formulations can be easy to mix up. “The optimized formulation is bioequivalent to the initial formulation, but lower doses of semaglutide are needed to achieve the same therapeutic effect,” wrote the institute, meaning the same number of milligrams does not produce the same therapeutic effect across the two versions.Why the dose is differentThe difference comes down to how the drug is absorbed: the new formulation uses modified excipients “to increase absorption (thereby increasing bioavailability),” writes ISMP Canada. Plainly, because more of the drug is absorbed, a smaller dose is needed to achieve the same therapeutic effect.The equivalent doses of the drug are 3 mg of the original formulation and 1.5 mg of the new formulation; 7 mg and 4 mg; and 14 mg and 9 mg. The tablets also look different: the new formulation is smaller and round, while the original is oval-shaped.ISMP Canada reported a second incident, this time involving a lower-than-intended dose. A prescription for 9 mg of the new formulation was dispensed as three 3-mg tablets of the original formulation, with instructions to take all three daily.But the three original tablets were equivalent to only 4.5 mg of the new formulation. The error was found during a medication review.Both versions remain in circulationUntil remaining supplies of the original formulation are used up, pharmacies and hospitals may carry both versions, with both appearing in electronic prescribing systems.ISMP Canada said pharmacists have reported a “difficulty in differentiating” between the formulations in electronic systems, as well as concerns about converting doses and having both versions on pharmacy shelves.Pharmacists can switch patients to the equivalent dose of the new formulation, said the institute, but should document the change and inform the prescriber.To reduce the risk of errors while both versions remain available, ISMP Canada recommends that pharmacy teams:clearly distinguish the original and new formulations in patient records, prescribing modules, pharmacy systems and medication administration records;add electronic alerts identifying the new formulation and showing dose-equivalency information;place a warning about dose equivalencies where Rybelsus is stored;deactivate drug files for the original formulation once remaining stock is depleted;explain changes in tablet strength, shape and size to patients and update their medication lists; andremind patients that Rybelsus should be taken as a “single tablet once daily” and that tablets should not be combined to make up a dose.

New and old tablets of this popular semaglutide will not have the same effect, warns ISMP Canada

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