Orphenadrine Citrate

INDICATIONS AND USAGE Orphenadrine citrate is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculo-skeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its analgesic properties. Orphenadrine citrate does not directly relax tense skeletal muscles in man.

DOSAGE AND ADMINISTRATION Adults: 2 mL (60 mg) intravenously or intramuscularly - May be repeated every 12 hours. Relief may be maintained by one (100 mg) orphenadrine citrate tablet twice daily. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever the solution and container permit.

CONTRAINDICATIONS Orphenadrine citrate is contraindicated in patients with glaucoma, pyloric or duodenal obstruction, stenosing peptic ulcers, prostatic hypertrophy or obstruction at the bladder neck, cardiospasm (megaesophagus) and myasthenia gravis. Orphenadrine citrate is contraindicated in patients who have demonstrated a previous hypersensitivity to the drug.

ADVERSE REACTIONS Adverse reactions of orphenadrine are mainly due to the mild anticholinergic 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 orphenadrine citrate.

DESCRIPTION Orphenadrine Citrate Injection is a sterile aqueous solution of orphenadrine citrate. It is intended for intravenous or intramuscular administration. Orphenadrine citrate is the citrate salt of orphenadrine and occurs as a white, crystalline powder having a bitter taste. It is practically odorless, sparingly soluble in water and slightly soluble in alcohol. It has the following structural formula: N,N-Dimethyl-2-[( o -methyl-α-phenylbenzyl)oxy]ethylamine Citrate (1:1). Each mL contains: Orphenadrine Citrate 30 mg, Sodium Metabisulfite 0.91 mg, Sodium Chloride 2.9 mg, in Water for Injection q.s. Sodium Hydroxide and/or Hydrochloric Acid may have been used to adjust pH. structural formula for orphenadrine citrate

OVERDOSAGE Orphenadrine is toxic when overdosed and typically induces anticholinergic effects. In a review of orphenadrine toxicity, the minimum lethal dose was found to be 2 to 3 grams for adults; however, the range of toxicity is variable and unpredictable. Treatment for orphenadrine overdose is evacuation of stomach contents (when necessary), charcoal at repeated doses, intensive monitoring, and appropriate supportive treatment of any emergent anticholinergic effects.

HOW SUPPLIED Orphenadrine Citrate Injection, USP is supplied as follows: Cartons of 10 ( NDC 0641-6182-10 ) 2 mL vials, each vial containing 60 mg of orphenadrine citrate in aqueous solution. Cartons of 25 ( NDC 0641-6182-25 ) 2 mL vials, each vial containing 60 mg of orphenadrine citrate in aqueous solution. Storage Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature]. Protect from light. Single dose vial. Discard unused portion. To report SUSPECTED ADVERSE REACTIONS, contact Hikma Pharmaceuticals USA Inc. at 1-877-845-0689, or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. For Product Inquiry call 1-877-845-0689. Manufactured by: Hikma Pharmaceuticals USA Inc. Berkeley Heights, NJ 07922 Revised May 2023 462-734-02