Shortage of orphenadrine citrate for injection

The American Society of Health-System Pharmacists reports a shortage of orphenadrine citrate for injection. Muscle and joint pain relief is the reason to use this drug. Muscle spasms in the back, muscle tension headaches, Parkinson’s disease muscle pain are all examples. It is used with amitriptyline, opioid pain relievers and other analgesics such as aspirin because of its additive effect on chronic pain. I suspect it is not much used unless the person seeking pain relief cannot take gabapentin for some reason.