Meperidine Shortage: Best Alternatives for Rigors

Meperidine Shortage Status

Meperidine (Demerol) is currently experiencing a significant shortage in the United States. Pfizer, a major supplier, has multiple meperidine injection products on back order, with estimated resupply dates ranging from July 2025 for 50 mg/mL vials to January 2026 for Carpuject syringes ¹ ³. The shortage is attributed to manufacturing delays ³.

Alternatives for Treating Rigors

Rigors, particularly those associated with medications such as rituximab or antithymocyte globulin (ATG), have traditionally been managed with meperidine due to its efficacy in reducing the shivering threshold ⁷. However, due to both safety concerns and ongoing shortages, alternative agents are being used.

Morphine as an Alternative

Efficacy: Recent studies and clinical practice have shown that intravenous morphine is an effective and safe alternative to meperidine for the treatment of rigors, especially those related to monoclonal antibody therapy (e.g., rituximab) and ATG ⁶⁸¹⁰.
Dosing: At Atrium Health Wake Forest Baptist, a protocol of 2 mg IV morphine at the onset of rigors, repeated after 15 minutes if necessary, has been effective. Most patients respond to one dose, with fatigue being the only significant adverse event noted ⁶⁸.
Comparison to Meperidine: While morphine may have a slightly slower onset compared to meperidine in some postoperative shivering studies, its efficacy for MAB-related rigors is comparable, with low rates of adverse events ¹⁰.

Other Pharmacologic Alternatives

Other Opioids: Agents such as fentanyl and hydromorphone may also be considered, though data are more limited and these drugs are also subject to periodic shortages ⁴⁹.
Non-opioid Options: For shivering and rigors, medications such as dexmedetomidine, midazolam, fentanyl, and magnesium sulfate have been shown to lower the shivering threshold and may serve as alternatives in specific clinical contexts ⁷.
Opioid-Sparing Agents: There is emerging interest in agents like intravenous ondansetron or clonidine, but further research is needed to clarify their role in treating drug-induced rigors ¹⁰.

Clinical Considerations

Morphine is a practical and effective alternative to meperidine for treating rigors, with protocols in place at some institutions.
Consider renal function and risk of adverse effects when selecting an alternative, as both meperidine and morphine can accumulate in renal impairment.
Non-opioid agents may be considered, especially if opioid use is contraindicated or in short supply.

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