Norflex N (Orphenadrine Citrate)

Orphenadrine citrate is used as a muscle relaxant to manage conditions involving skeletal muscle spasm.

• Muscle spasm: provides relief of involuntary muscle contraction and associated pain.
• Acute musculoskeletal pain: reduces pain intensity and improves mobility during the early phase of injury.
• Muscle injury adjunct therapy: supports recovery by decreasing muscle tone and facilitating physiotherapy.

• Orphenadrine citrate exerts its effect primarily by antagonizing muscarinic acetylcholine receptors in the central nervous system, leading to reduced cholinergic transmission and muscle tone. It also blocks histamine H1 receptors and displays NMDA receptor antagonism, contributing to central muscle relaxation and analgesic properties. The combined receptor blockade diminishes reflex muscle activity and attenuates pain signaling pathways, which together produce the therapeutic muscle‑relaxing effect observed in acute injury settings.

Orphenadrine citrate may cause a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Dry mouth: reduced salivary flow leading to throat discomfort and increased thirst.
• Drowsiness: mild to moderate sedation that may affect concentration and driving ability.
• Dizziness: sensation of light‑headedness or imbalance, often occurring when changing posture.
• Blurred vision: temporary visual disturbances such as difficulty focusing.

Serious or Rare Side Effects

• Cardiac arrhythmia: irregular heart rhythm that can be symptomatic and may require monitoring.
• Severe hypotension: significant drop in blood pressure causing faintness, dizziness, or shock.
• Allergic reaction: skin rash, itching, swelling, or anaphylaxis that necessitates immediate medical care.

When using Orphenadrine citrate, several precautions should be observed to ensure safe administration.

• Assess cardiac history: evaluate for pre‑existing arrhythmias or conduction disorders.
• Monitor blood pressure: watch for hypotensive episodes, especially in dehydrated patients.
• Use caution in the elderly: increased sensitivity to sedative and anticholinergic effects.
• Avoid concurrent CNS depressants: limit use with alcohol, opioids, or benzodiazepines.
• Review hepatic and renal function: adjust therapy if significant impairment is present.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Orphenadrine citrate can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• MAO inhibitors: risk of hypertensive crisis or severe CNS effects.
• Anticholinergic burden: concurrent strong anticholinergics may exacerbate dry mouth, urinary retention, and cognitive impairment.

Moderate Interactions (Monitor Closely)

• CNS depressants: additive sedation when combined with opioids, benzodiazepines, or antihistamines.
• Beta‑blockers: may mask tachycardia caused by anticholinergic activity.
• QT‑prolonging agents: potential increase in cardiac arrhythmia risk.