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Last reviewed on RxList: 10/19/2010
Norflex Side Effects Center

Last reviewed on RxList 7/28/2016

Norflex (orphenadrine citrate 100mg) is a muscle relaxant used to treat muscle spasms/pain. Norflex is usually used along with rest, physical therapy, and other treatment. Norflex is available in generic form. Common side effects of Norflex include

  • dry mouth or throat,
  • headache,
  • dizziness,
  • drowsiness,
  • lightheadedness,
  • weakness,
  • blurred vision,
  • dilated pupils,
  • nausea,
  • vomiting, and
  • constipation.

Tell your doctor if you experience serious side effects of Norflex including

  • fast, pounding, or uneven heartbeats,
  • confusion,
  • anxiety,
  • agitation,
  • tremors,
  • hallucinations;
  • seizures (convulsions); or
  • urinating less than usual or not at all.



This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Norflex Consumer Information

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

Stop using orphenadrine and call your doctor at once if you have any of these serious side effects:

  • fast, pounding, or uneven heartbeats;
  • confusion, anxiety, agitation, tremors, hallucinations;
  • seizure (convulsions); or
  • urinating less than usual or not at all.

Less serious side effects may include:

  • dry mouth or throat;
  • blurred vision, dilated pupils;
  • headache;
  • drowsiness, dizziness;
  • nausea, vomiting, constipation; or
  • weakness.

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.

Read the entire detailed patient monograph for Norflex (Orphenadrine Injection)

Norflex Professional Information


Adverse reactions of orphenadrine are mainly due to the mild anti-cholinergic action of orphenadrine, and are usually associated with higher dosage. Dryness of the mouth is usually the first adverse effect to appear. When the daily dose is increased, possible adverse effects include: tachycardia, palpitation, urinary hesitancy or retention, blurred vision, dilatation of pupils, increased ocular tension, weakness, nausea, vomiting, headache, dizziness, constipation, drowsiness, hypersensitivity reactions, pruritus, hallucinations, agitation, tremor, gastric irritation, and rarely urticaria and other dermatoses. Infrequently, an elderly patient may experience some degree of mental confusion. These adverse reactions can usually be eliminated by reduction in dosage. Very rare cases of aplastic anemia associated with the use of orphenadrine tablets have been reported. No causal relationship has been established.

Rare instances of anaphylactic reaction have been reported associated with the intramuscular injection of Norflex (orphenadrine) Injection.

Drug Abuse And Dependence

Orphenadrine has been chronically abused for its euphoric effects. The mood elevating effects may occur at therapeutic doses of orphenadrine.

Read the entire FDA prescribing information for Norflex (Orphenadrine Injection)

Related Resources for Norflex

Read the Norflex User Reviews »

© Norflex Patient Information is supplied by Cerner Multum, Inc. and Norflex Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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