英文药名: Norflex(Orphenadrine Injection)
中文参考药名: 奥芬那君注射剂
生产厂家: 3M Pharmaceuticals
奥芬那君注射剂药品简介
枸橼酸奥芬那君（枸橼酸邻甲苯海拉明，柠檬酸邻甲苯海拉明）
英文名称：Orphenadrine Citrate(Mephenamine Citrate,Norflex)
性状：白色或近白色结晶粉末，几无臭，味苦。溶于水，微溶于乙醇，不溶于氯仿或乙醚。
作用机制：
本品结构与抗组胺药苯海拉明类似，作用于大脑和脊髓运动中枢，使骨骼肌松驰。本品尚具有较弱的外周抗胆碱和抗胺作用，但镇静作用弱。 本品对痉挛性或运动障碍性运动病无效。
药动学：
口服吸收较好，大部分被代谢，平均血浆t1/2约为14h。
适应症：
临床主要用作解除局部肌肉痉挛性疼痛的辅助用药，也常与其他药物联合用于控制动脉硬化引起的特发性或脑炎后的震颤麻痹。
注意事项：
(1)本品的不良反应主要与其抗胆碱活性有关，常见的有视物模糊，口和皮肤干燥，轻度兴奋。
(2)本品标用于闭角型青光眼及重症肌无力患者。心动过速、心功能不全或尿潴留患者慎用。
(3)服用本品期间避免进行注意力须高度集中的活动如驾驶、登高、操作精密仪器等。
用法用量：
口服：成人，100mg/次，2次/d。
肌内或静脉注射，成人，60mg/次，2次/d。
制剂：片剂：100mg。注射液：30mg/1ml。
包装规格：
30mg/ml（6支 x 2ml）
Norflex
Generic Name: orphenadrine citrate
Dosage Form: injection
Norflex Description
Orphenadrine citrate is the citrate salt of orphenadrine (2-dimethylaminoethyl 2-methylbenzhydryl ether citrate). It occurs as a white, crystalline powder having a bitter taste. It is practically odorless; sparingly soluble in water, slightly soluble in alcohol.
Norflex Injection contains 60 mg of orphenadrine citrate in aqueous solution in each ampul. Norflex Injection also contains: sodium bisulfite NF, 2.0 mg; sodium chloride USP, 5.8 mg; sodium hydroxide, to adjust pH; and water for injection USP, q.s. to 2 mL.
Norflex - Clinical Pharmacology
The mode of therapeutic action has not been clearly identified, but may be related to its analgesic properties. Orphenadrine citrate does not directly relax tense muscles in man. Orphenadrine citrate also possesses anti-cholinergic actions.
Indications and Usage for Norflex
Orphenadrine citrate is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions.
Contraindications
Contraindicated in patients with glaucoma, pyloric or duodenal obstruction, stenosing peptic ulcers, prostatic hypertrophy or obstruction of the bladder neck, cardio-spasm (megaesophagus) and myasthenia gravis.
Contraindicated in patients who have demonstrated a previous hypersensitivity to the drug.
Warnings
Some patients may experience transient episodes of light-headedness, dizziness or syncope. Norflex may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; ambulatory patients should therefore be cautioned accordingly.
Norflex Injection contains sodium bisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than nonasthmatic people.
Precautions
Confusion, anxiety and tremors have been reported in few patients receiving propoxyphene and orphenadrine concomitantly. As these symptoms may be simply due to an additive effect, reduction of dosage and/or discontinuation of one or both agents is recommended in such cases.
Orphenadrine citrate should be used with caution in patients with tachycardia, cardiac decompensation, coronary insufficiency, and cardiac arrhythmias.
Safety of continuous long-term therapy with orphenadrine has not been established. Therefore, if orphenadrine is prescribed for prolonged use, periodic monitoring of blood, urine and liver function values is recommended.
PREGNANCY
Pregnancy Category C. Animal reproduction studies have not been conducted with Norflex. It is also not known whether Norflex can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Norflex should be given to a pregnant woman only if clearly needed.
PEDIATRIC USE
Safety and effectiveness in pediatric patients have not been established.
Adverse Reactions
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 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.
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 2-3 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.
Norflex Dosage and Administration
INJECTION: Adults - One 2 mL ampul (60 mg) intravenously or intramuscularly; may be repeated every 12 hours.
How is Norflex Supplied
INJECTION: Boxes of 6 (NDC 29336-540-06) 2 mL ampuls, each ampul containing 60 mg of orphenadrine citrate in aqueous solution.
Store at controlled room temperature 15°-30°C (59°-86°F).