Norflex (Orphenadrine Citrate)

Orphenadrine citrate acts as a central muscle‑relaxant for conditions involving skeletal muscle spasm.

• Muscle spasm: reduces involuntary muscle contraction and associated discomfort.
• Musculoskeletal pain: alleviates pain linked to acute musculoskeletal injuries.
• Acute low‑back pain: improves mobility and eases tension in the lumbar region.

• Orphenadrine citrate exerts anticholinergic activity by blocking muscarinic receptors in the central nervous system, which diminishes reflex muscle hyperactivity. Its central muscle‑relaxant effect is thought to involve inhibition of spinal interneuron transmission, leading to reduced muscle tone and relief of spasm without direct peripheral muscle paralysis.

Orphenadrine citrate may cause a range of adverse reactions, most of which are dose‑related and reversible.

Common Side Effects

• Dry mouth: reduced salivary secretion causing throat discomfort.
• Drowsiness: mild sedation affecting alertness.
• Dizziness: sensation of light‑headedness, especially when standing quickly.
• Nausea: mild gastrointestinal upset.

Serious or Rare Side Effects

• Tachycardia: rapid heart rate that may require medical attention.
• Urinary retention: difficulty emptying the bladder, particularly in predisposed individuals.
• Severe allergic reaction: rash, swelling, or anaphylaxis requiring immediate care.
• Hepatic dysfunction: abnormal liver enzymes or jaundice in rare cases.

Before initiating therapy with Orphenadrine citrate, consider the following safety measures.

• Cardiac assessment: evaluate history of arrhythmias or heart disease.
• Anticholinergic burden: monitor for excessive dry mouth, blurred vision, or constipation.
• Elderly patients: use lower doses and observe for confusion or falls.
• CNS depressants: avoid concurrent use with alcohol or strong sedatives.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Orphenadrine citrate can interact with several medication classes; awareness helps prevent adverse outcomes.

Major Interactions (Avoid)

• MAO inhibitors: risk of hypertensive crisis.
• Tricyclic antidepressants: additive anticholinergic effects.
• Other anticholinergics: heightened dry mouth and urinary retention.
• CNS depressants: increased sedation and respiratory depression.
• Alcohol: potentiates drowsiness and dizziness.

Moderate Interactions (Monitor Closely)

• Antihistamines: may enhance sedation.
• Beta‑blockers: possible additive effect on heart rate.
• Antihypertensives: monitor blood pressure for unexpected changes.