Skip to Content

Orphenadrine

Generic Name: orphenadrine (or FEN a drin)
Brand Name: Norflex, ...show all 10 brand names

Medically reviewed: March 10, 2017

What is orphenadrine?

Orphenadrine is a muscle relaxer.

Orphenadrine is used together with rest and physical therapy to treat skeletal muscle conditions such as pain or injury.

Orphenadrine may also be used for purposes not listed in this medication guide.

Important Information

You should not take this medicine if you have urination problems, an enlarged prostate, glaucoma, a stomach ulcer or blockage in your digestive tract, trouble swallowing, or myasthenia gravis.

Before taking this medicine

You should not use orphenadrine if you are allergic to it, or if you have:

  • urination problems;

  • an enlarged prostate;

  • glaucoma;

  • a stomach ulcer;

  • a blockage in your stomach or intestines;

  • trouble swallowing; or

  • myasthenia gravis.

To make sure orphenadrine is safe for you, tell your doctor if you have:

  • heart disease;

  • a heart rhythm disorder;

  • coronary artery disease; or

  • if you also use a narcotic (opioid) medication.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether orphenadrine passes into breast milk or if it could affect the nursing baby. Tell your doctor if you are breast-feeding.

Orphenadrine is not approved for use by anyone younger than 18 years old.

How should I take orphenadrine?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Orphenadrine may be habit-forming. Never share orphenadrine with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it. Selling or giving away this medicine is against the law.

Orphenadrine is usually taken 2 times per day, once in the morning and once in the evening. Follow your doctor's dosing instructions.

Do not crush, chew, or break an extended-release tablet. Swallow it whole.

Orphenadrine is only part of a complete program of treatment that may also include rest, physical therapy, or other pain relief measures.

Store orphenadrine at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

Keep track of the amount of medicine used from each new bottle. Orphenadrine is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking orphenadrine?

This medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Do not drink alcohol. Dangerous side effects or death can occur.

Orphenadrine side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using orphenadrine and call your doctor at once if you have:

  • a light-headed feeling, like you might pass out;

  • painful or difficult urination;

  • little or no urination;

  • confusion, anxiety, agitation, tremors, hallucinations; or

  • pounding heartbeats or fluttering in your chest.

Common side effects may include:

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Orphenadrine dosing information

Usual Adult Dose for Muscle Spasm:

Acute musculoskeletal conditions:

100 mg orally twice a day (morning and evening).

-or-

60 mg by intramuscular or intravenous injection. May repeat every 12 hours.

Quinine-resistant leg cramps:

100 mg orally at bedtime.

What other drugs will affect orphenadrine?

Taking orphenadrine with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before taking a sleeping pill, narcotic pain medicine, prescription cough medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.

Other drugs may interact with orphenadrine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Hide