Orphenadrine

Information about Orphenadrine

Orphenadrine is a centrally acting muscle relaxant that has been in clinical use for more than 50 years and has not been linked to liver injury or clinically apparent drug induced liver disease.

Mechanism of action of Orphenadrine

Orphenadrine (or fen' a dreen) is a centrally acting, nonopiate analgesic and muscle relaxant.  It is a methyl derivative of diphenhydramine (a commonly used antihistamine), but its mechanism of action in causing analgesia and skeletal muscle relaxation is not well defined.  Orphenadrine has anticholinergic activity and may act centrally on pain perception. 

FDA approval information for Orphenadrine

Orphenadrine is currently used for the treatment of acute, painful musculoskeletal conditions and can be given orally or parenterally.  Orphenadrine was approved for use as a muscle relaxant in the United States in 1957 and it is still in wide use. 

Brand name for Orphenadrine

Orphenadrine is available in multiple generic forms as standard and extended release tablets of 100 mg.  It is also available under commercial names such as Norgesic, Norflex, Deenar, Banflex, Disipal and X-Otag.  The recommended dosage is 100 mg twice daily.  Orphenadrine is also available in parenteral formulations under the names of Flexoject and Myolin.  The parenteral dose recommendation is 60 mg either intravenously or intramuscularly twice daily. 

Side effects of Orphenadrine

The most common side effects are those typical of anticholinergics including drowsiness, dry mouth, diaphoresis, flushing, confusion and visual disturbances.  Orphenadrine also has a potential for abuse and fatal overdoses have been reported.

Muscle relaxants

• Baclofen
• Carisoprodol
• Chlorzoxazone
• Cyclobenzaprine
• Dantrolene
• Metaxalone
• Methocarbamol
• Orphenadrine
• Tizanidine

• Dailymed label info on Orphenadrine
• FDA Orphenadrine

Orphenadrine

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  Orphenadrine
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  (R)-Orphenadrine Structural Formula
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  (S)-Orphenadrine Structural Formula