Generic Name: Orphenadrine Citrate
Class: Skeletal Muscle Relaxants, Miscellaneous
VA Class: MS200
CAS Number: 341-69-5
Introduction
Skeletal muscle relaxant; tertiary amine antimuscarinic.a b c d k
Uses for Norflex
Muscular Conditions
Used alone or in combination with aspirin and caffeine as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions.a b c k
For low back pain, generally reserve skeletal muscle relaxants for adjunctive treatment when pain is unresponsive to OTC analgesics (e.g., NSAIAs).d e f g h i
Skeletal muscle relaxants less well tolerated than NSAIAs, and clinical superiority to NSAIAs not established for low back pain.d e f g h i
Various skeletal muscle relaxants appear to have comparable efficacy for low back pain reliefj d and are more effective than placebo.d f h
Initially, symptomatic control of acute low back pain focuses on providing sufficient comfort to allow maximum possible activity while awaiting spontaneous recovery; later, as an aid to overcome specific activity intolerance.h
Because of rapid spontaneous recovery rate, efficacy of various therapies may be difficult to establish;h improvement of low back pain usually occurs within 2 weeks, substantial improvement within 4 weeks.g
Norflex Dosage and Administration
Administration
Administer orally or by IV or IM injection.a b c k
Switch from parenteral to oral therapy as soon as possible.c
Oral Administration
Administer orphenadrine citrate extended-release tablets orally twice daily.b c
Administer orphenadrine citrate fixed-combination tablets (with aspirin and caffeine) orally 3 or 4 times daily.k
IV Administration
Place patient in supine position during and for 5–10 minutes following IV injection.c (See CNS Effects under Cautions.) To minimize adverse reactions, assist patient from recumbent position.c
Rate of Administration
Administer IV over about 5 minutes.c
Dosage
Available as orphenadrine citrate; dosage expressed in terms of the salt.a b
Adults
Muscular Conditions
Therapy with Extended-release Tablets
Oral
100 mg twice daily.a b
Therapy with Orphenadrine Fixed-combination Tablets
Oral
25–50 mg (in combination with aspirin 385–770 mg and caffeine 30–60 mg) 3 or 4 times daily.k
Parenteral Therapy
IV or IM
60 mg every 12 hours.a b
Cautions for Norflex
Contraindications
Glaucoma.a b k
Pyloric or duodenal obstruction.a b k
Stenosing peptic ulcers.a b
Prostatic hypertrophy or obstruction of the bladder neck.a b k
Cardiospasm (megaesophagus).a b
Myasthenia gravis.a b k
Known hypersensitivity to orphenadrine or any ingredient in the formulation.a b k
Warnings/Precautions
Warnings
CNS Effects
Transient episodes of light-headedness, dizziness, or syncope reported.a b k
Performance of activities requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle) may be impaired.a b k
Sensitivity Reactions
Sulfite Sensitivity
Injectable formulation contains sodium bisulfite, which can cause allergic-type reactions, including anaphylaxis and life-threatening or less severe asthmatic episodes, in certain susceptible individuals.100 a b
Overall prevalence of sulfite sensitivity in the general population unknown but probably low; such sensitivity appears to occur more frequently in asthmatic than in nonasthmatic individuals.100 a b
General Precautions
Adequate Patient Monitoring
Safety of continuous therapy not established.a b k Perform periodic blood, urine, and liver function tests during prolonged orphenadrine therapy.c k
Cardiac Effects
Possible tachycardia and palpitation; may be associated with increased dosages.a b Use with caution in patients with tachycardia, cardiac decompensation, coronary insufficiency, or cardiac arrhythmias.a b
Use of Fixed Combinations
When orphenadrine is used in fixed combination with aspirin and caffeine, consider the cautions, precautions, and contraindications associated with each agent in the combination.k
Specific Populations
Pregnancy
Category C.a b
Lactation
Not known whether orphenadrine is distributed into milk; use with caution.c
Pediatric Use
Safety and efficacy not established in children <12 years of age.c
Common Adverse Effects
Dry mouth,a b d k tachycardia,a b k palpitation,a b k urinary hesitancy or retention,a b k blurred vision,a b k dilatation of pupils,a b k increased intraocular pressure,a b k weakness,a b k nausea,a b k vomiting,a b k headache,a b k diziness,a b k constipation,a b k drowsiness.a b k
Interactions for Norflex
Specific Drugs
Drug | Interaction | Comments |
|---|---|---|
Propoxyphene | Potential additive CNS effectsa b c k | Reduce dosage and/or discontinue one or both agents if adverse CNS effects develop during concomitant therapya b c k |
Norflex Pharmacokinetics
Absorption
Bioavailability
Readily absorbed following oral administration.c
Distribution
Extent
Distribution not fully characterized in humans.c In animals, detected in all organs, especially those with greatest perfusion (e.g., lungs).c
Orphenadrine may cross the placenta; not known whether distributed into milk.c
Elimination
Metabolism
Almost completely metabolized to at least 8 metabolites; however, metabolic fate not fully determined.c
Elimination Route
Eliminated principally in urine as metabolites and, in small amounts, as unchanged drug.c
Half-life
Approximately 14 hours.c
Stability
Storage
Oral
Tablets
15–30°C.b c k
Parenteral
Injection
15–30°C.a b c Do not freeze; protect from light.c
ActionsActions
CNS depressant with skeletal muscle relaxant effects.c
Precise mechanism of action not known.a k Does not directly relax skeletal muscle;a b c k therapeutic action may be related to analgesic properties.a c k
May reduce skeletal muscle spasm, possibly through an atropine-like central action on cerebral motor centers or on the medulla.c
Exhibits postganglionic anticholinergic,a c antihistaminicc , and local anesthetic properties.c
Advice to Patients
Potential to impair mental alertness or physical coordination; use caution when driving or operating machinery until effects on individual are known.a b k
Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as concomitant illnesses.a b k
Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.a b k
Importance of informing patients of other important precautionary information.a b k (See Cautions.)
Preparations
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Tablets, extended-release | 100 mg* | Norflex | 3M |
Orphenadrine Citrate Tablets | Actavis, Global, Kiel, Sandoz | |||
Parenteral | Injection | 30 mg/mL* | Norflex (with sodium bisulfite) | 3M |
Orphenadrine Citrate Injection | Akorn, Bedford, Watson |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Tablets | 25 mg with Aspirin 385 mg and Caffeine 30 mg* | Norgesic (with povidone) | 3M |
Orphenadrine Citrate, Aspirin, and Caffeine Tablets | Sandoz | |||
50 mg with Aspirin 770 mg and Caffeine 60 mg* | Norgesic Forte (with povidone; scored) | 3M | ||
Orphenadrine Citrate, Aspirin, and Caffeine Tablets | Sandoz |
Comparative Pricing
This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 03/2011. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.
Orphenadrine Citrate CR 100MG 12-hr Tablets (GLOBAL PHARMACEUTICAL CORP): 30/$48.99 or 90/$141.98
Disclaimer
This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.
The American Society of Health-System Pharmacists, Inc. and Drugs.com represent that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. and Drugs.com make no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. and Drugs.com do not endorse or recommend the use of any drug. The information is not a substitute for medical care.
AHFS Drug Information. © Copyright, 1959-2011, Selected Revisions August 2008. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.
References
Only references cited for selected revisions after 1984 are available electronically.
100. Food and Drug Administration. Sulfiting agents; labeling in drugs for human use; warning statements. [21 CFR Part 201] Fed Regist. 1986; 51:43900-5.
a. Hospira, Inc. Norflex (orphenadrine citrate) injection prescribing information. Lake Forest, IL; 2004 Jul.
b. 3M Pharmaceuticals. Norflex 9orphenadrine citrate) extended-release tablets and injection prescribing information. Northridge, CA; 2000 Jul.
c. AHFS drug information 2007. McEvoy GK, ed. Orphenadrine Citrate. Bethesda, MD: American Society of Health-System Pharmacists; 2007:1398-9.
d. van Tulder MW, Touray T, Furlan AD et al. Muscle relaxants for non-specific low back pain. Cochrane Database of Systematic Reviews. 2003, Issue 4. Art. No.: CD004252. DOIL 10.1002414651858. CD004252.
e. van Tulder MW, Scholten RJPM, Kowes BW, et al. Non-steroidal anti-inflammatory drugs for low back pain. The Cochrane Library. From their web site (). Accessed 11/10/2003.
f. Department of Veterans Affairs Veterans Health Administration Office of Quality & Performance. Management of Person with Low Back Pain/Sciatica in Primary Care. From the web site (). Accessed 8/25/2003.
g. Agency for Healthcare Research and Quality. Adult low back pain. From the National Guideline Clearinghouse website. (). Accessed 8/25/2003.
h. U.S. Department of Health and Human Services. Public Health Service. Agency for Halath Care Policy and Research. Acute low back problems in adults. Clinical Practice Guideline.1994; No. 14
i. U.S. Department of Health and Human Services. Public Health Service. Agency for Health Care Policy and Research. Acute low back problems in adults: Assessment and treatment. Clinical Practice Guideline. Quick Reference Guide for Clinicians.1994; No. 14
j. McNeil. Cyclobenzaprine hydrochloride (Flexeril) tablets prescribing information. Fort Washington, PA: 2003 Feb.
k. 3M Pharmaceuticals. Norgesic and Norgesic Forte tablets prescribing information. Northridge, CA; 1998 May.
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