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Different concentrations of oral liquid baclofen

FLEQSUVY (baclofen) oral suspension (25 mg/5 mL [5 mg/mL]) is a new formulation of the skeletal muscle relaxant used to treat spasticity from multiple sclerosis and may also be used for patients with spinal cord injuries and other diseases. OZOBAX is another brand of baclofen oral solution that was available before Fleqsuvy. But Ozobax comes in a different strength, 5 mg/5 mL (1 mg/mL), than Fleqsuvy, 25 mg/ 5 mL (5 mg/mL). The Ozobax label lists the concentration as “5 mg/5 mL,” which could be confused with the 5 mg/mL strength of Fleqsuvy, although Fleqsuvy is primarily labeled 25 mg/5 mL. Prior to the availability of both commercial products, ISMP had received several reports related to confusion between various compounded baclofen concentrations. If a patient receives an under- or overdose due to a concentration error, either inadequate treatment and withdrawal syndrome, or baclofen toxicity could result. Both the American Society of Health-System Pharmacists and the Michigan Pediatric Safety Collaboration recommend a concentration of 5 mg/mL for compounded baclofen oral liquid prescriptions.

When possible, organizations should standardize to a single concentration of baclofen based on the patient population served—avoid adding both Fleqsuvy and Ozobax to the organization’s formulary. Electronic health records should be configured to list the concentration of the available product (i.e., 25 mg/5 mL [5 mg/mL] or 5 mg/5 mL [1 mg/mL]). Practitioners should be made aware of the potential for error due to the different concentrations on the market, with special attention given during the medication reconciliation process to ensure accurate doses are documented and prescribed. Doses should be prescribed in mg, and practitioners should clarify and discuss doses based on the mg dose. Also, ensure that automatic substitutions account for the different strengths of the drug, or do not allow automatic substitutions or interchanges. Using the teach-back method, pharmacists and nurses should also educate patients and/or caregivers about the concentration, the corresponding volumetric dose, and how to measure each dose with an oral syringe.

Suggested citation:

Institute for Safe Medication Practices (ISMP). Different concentrations of oral liquid baclofen. ISMP Medication Safety Alert! Acute Care. 2022;27(11):4.