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Norflex Side Effects

Generic name: orphenadrine

Medically reviewed by Last updated on Feb 7, 2024.

Note: This document contains side effect information about orphenadrine. Some dosage forms listed on this page may not apply to the brand name Norflex.

Applies to orphenadrine: oral tablet extended release. Other dosage forms:

Serious side effects of Norflex

Along with its needed effects, orphenadrine (the active ingredient contained in Norflex) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking orphenadrine:


Incidence not known

Get emergency help immediately if any of the following symptoms of overdose occur while taking orphenadrine:

Symptoms of Overdose

Other side effects of Norflex

Some side effects of orphenadrine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common or rare

Incidence not known

For Healthcare Professionals

Applies to orphenadrine: compounding powder, injectable solution, oral tablet extended release.


The more commonly reported adverse reactions are due to the anticholinergic effects of this drug; dry mouth is usually the first adverse effect to appear.


Rare (less than 0.1%): Anaphylaxis (with IM injection)

Frequency not reported: Hypersensitivity reactions

Nervous system

Frequency not reported: Headache, light-headedness, dizziness, drowsiness, syncope, tremor, sedation, convulsions, coordination difficulties[Ref]


Rare (less than 0.1%): Memory disturbances

Frequency not reported: Hallucinations, agitation, euphoria, restlessness, mental confusion (especially elderly)[Ref]


Frequency not reported: Blurred vision, dilatation of pupils, increased ocular tension, accommodation disorders[Ref]


Frequency not reported: Tachycardia, palpitations[Ref]


Frequency not reported: Dry mouth, nausea, vomiting, constipation, gastric irritation[Ref]


Frequency not reported: Urinary hesitancy, urinary retention[Ref]


Frequency not reported: Weakness[Ref]


Rare (less than 0.1%): Urticaria, other dermatoses

Frequency not reported: Pruritus[Ref]


Rare (less than 0.1%): Aplastic anemia[Ref]


1. (2001) "Product Information. Norflex (orphenadrine)." 3M Pharmaceuticals

Further information

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

Some side effects may not be reported. You may report them to the FDA.