orphenadrine (Rx)

Brand and Other Names:Norflex

Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

injectable solution

  • 30mg/mL

tablet, extended release

  • 100mg

Muscle Spasm & Pain

Indicated for muscle spasm and relief of discomfort associated with acute painful musculoskeletal conditions

100 mg PO q12hr OR

60 mg IV/IM q12hr (switch to PO as soon as possible)

Other Indications & Uses

Off-label: Leg cramps resistant to quinine, Parkinson's disease

Safety and efficacy not established

Caution; not recommended for use in elderly because of increased sedation and anticholinergic effects

Muscle spasm, relief of discomfort associated with acute painful musculoskeletal conditions

100 mg PO q12hr OR

60 mg IV/IM q12hr (switch to PO as soon as possible)

Next:

Interactions

Interaction Checker

and orphenadrine

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            Contraindicated (1)

            • fezolinetant

              orphenadrine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

            Serious - Use Alternative (15)

            • benzhydrocodone/acetaminophen

              benzhydrocodone/acetaminophen, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

              benzhydrocodone/acetaminophen and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

            • buprenorphine subdermal implant

              buprenorphine subdermal implant and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

            • buprenorphine transdermal

              buprenorphine transdermal and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

            • buprenorphine, long-acting injection

              buprenorphine, long-acting injection and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

            • calcium/magnesium/potassium/sodium oxybates

              orphenadrine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • clonidine

              clonidine, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Enhanced CNS depressant effects.

            • fedratinib

              orphenadrine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

            • glucagon

              glucagon increases toxicity of orphenadrine by Other (see comment). Avoid or Use Alternate Drug. Comment: Coadministration of anticholinergic drugs and glucagon increase the risk of gastrointestinal adverse reactions due to additive effects on inhibition of gastrointestinal motility. .

            • glucagon intranasal

              glucagon intranasal increases toxicity of orphenadrine by Other (see comment). Avoid or Use Alternate Drug. Comment: Coadministration of anticholinergic drugs and glucagon increase the risk of gastrointestinal adverse reactions due to additive effects on inhibition of gastrointestinal motility. .

            • hydrocodone

              hydrocodone, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • lonafarnib

              orphenadrine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

            • metoclopramide intranasal

              orphenadrine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

            • olopatadine intranasal

              orphenadrine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

            • sodium oxybate

              orphenadrine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • sufentanil SL

              sufentanil SL, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            Monitor Closely (214)

            • abobotulinumtoxinA

              orphenadrine increases effects of abobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

              abobotulinumtoxinA increases effects of orphenadrine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

            • aclidinium

              aclidinium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • acrivastine

              acrivastine and orphenadrine both increase sedation. Use Caution/Monitor.

            • alfentanil

              orphenadrine and alfentanil both increase sedation. Use Caution/Monitor.

            • alprazolam

              alprazolam and orphenadrine both increase sedation. Use Caution/Monitor.

            • amisulpride

              amisulpride and orphenadrine both increase sedation. Use Caution/Monitor.

            • amitriptyline

              amitriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and amitriptyline both increase sedation. Use Caution/Monitor.

            • amobarbital

              amobarbital and orphenadrine both increase sedation. Use Caution/Monitor.

            • amoxapine

              amoxapine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and amoxapine both increase sedation. Use Caution/Monitor.

            • anticholinergic/sedative combos

              anticholinergic/sedative combos and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • apomorphine

              orphenadrine and apomorphine both increase sedation. Use Caution/Monitor.

            • aripiprazole

              orphenadrine and aripiprazole both increase sedation. Use Caution/Monitor.

            • asenapine

              asenapine and orphenadrine both increase sedation. Use Caution/Monitor.

            • asenapine transdermal

              asenapine transdermal and orphenadrine both increase sedation. Use Caution/Monitor.

            • atracurium

              atracurium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • atropine

              atropine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • atropine IV/IM

              atropine IV/IM and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • avapritinib

              orphenadrine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              avapritinib and orphenadrine both increase sedation. Use Caution/Monitor.

            • axitinib

              orphenadrine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • azelastine

              azelastine and orphenadrine both increase sedation. Use Caution/Monitor.

            • baclofen

              baclofen and orphenadrine both increase sedation. Use Caution/Monitor.

            • belladonna alkaloids

              belladonna alkaloids and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • belladonna and opium

              belladonna and opium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and belladonna and opium both increase sedation. Use Caution/Monitor.

            • benperidol

              orphenadrine and benperidol both increase sedation. Use Caution/Monitor.

            • benzphetamine

              orphenadrine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • benztropine

              benztropine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use.

            • bethanechol

              bethanechol increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • brexanolone

              brexanolone, orphenadrine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

            • brexpiprazole

              brexpiprazole and orphenadrine both increase sedation. Use Caution/Monitor.

            • brimonidine

              brimonidine and orphenadrine both increase sedation. Use Caution/Monitor.

            • brivaracetam

              brivaracetam and orphenadrine both increase sedation. Use Caution/Monitor.

            • brompheniramine

              brompheniramine and orphenadrine both increase sedation. Use Caution/Monitor.

            • buprenorphine

              orphenadrine and buprenorphine both increase sedation. Use Caution/Monitor.

            • buprenorphine buccal

              orphenadrine and buprenorphine buccal both increase sedation. Use Caution/Monitor.

            • buprenorphine, long-acting injection

              buprenorphine, long-acting injection increases effects of orphenadrine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Buprenorphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and increase risk for respiratory depression. Monitor for signs of respiratory depression that may be greater than otherwise expected and decrease muscle relaxant dosage as necessary.

            • butabarbital

              butabarbital and orphenadrine both increase sedation. Use Caution/Monitor.

            • butalbital

              butalbital and orphenadrine both increase sedation. Use Caution/Monitor.

            • butorphanol

              orphenadrine and butorphanol both increase sedation. Use Caution/Monitor.

            • carbachol

              carbachol increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • carbinoxamine

              carbinoxamine and orphenadrine both increase sedation. Use Caution/Monitor.

            • carisoprodol

              carisoprodol and orphenadrine both increase sedation. Use Caution/Monitor.

            • cevimeline

              cevimeline increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • chloral hydrate

              chloral hydrate and orphenadrine both increase sedation. Use Caution/Monitor.

            • chlordiazepoxide

              chlordiazepoxide and orphenadrine both increase sedation. Use Caution/Monitor.

            • chlorpheniramine

              chlorpheniramine and orphenadrine both increase sedation. Use Caution/Monitor.

            • chlorpromazine

              orphenadrine and chlorpromazine both increase sedation. Use Caution/Monitor.

            • chlorzoxazone

              chlorzoxazone and orphenadrine both increase sedation. Use Caution/Monitor.

            • cinnarizine

              cinnarizine and orphenadrine both increase sedation. Use Caution/Monitor.

            • cisatracurium

              cisatracurium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • clemastine

              clemastine and orphenadrine both increase sedation. Use Caution/Monitor.

            • clomipramine

              clomipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and clomipramine both increase sedation. Use Caution/Monitor.

            • clonazepam

              clonazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • clorazepate

              clorazepate and orphenadrine both increase sedation. Use Caution/Monitor.

            • clozapine

              orphenadrine and clozapine both increase sedation. Use Caution/Monitor.

            • codeine

              orphenadrine and codeine both increase sedation. Use Caution/Monitor.

            • cyclizine

              cyclizine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              cyclizine and orphenadrine both increase sedation. Use Caution/Monitor.

            • cyclobenzaprine

              cyclobenzaprine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              cyclobenzaprine and orphenadrine both increase sedation. Use Caution/Monitor.

            • cyproheptadine

              cyproheptadine and orphenadrine both increase sedation. Use Caution/Monitor.

            • dantrolene

              dantrolene and orphenadrine both increase sedation. Use Caution/Monitor.

            • daridorexant

              orphenadrine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

            • darifenacin

              darifenacin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • desipramine

              desipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and desipramine both increase sedation. Use Caution/Monitor.

            • dexchlorpheniramine

              dexchlorpheniramine and orphenadrine both increase sedation. Use Caution/Monitor.

            • dexfenfluramine

              orphenadrine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dexmedetomidine

              dexmedetomidine and orphenadrine both increase sedation. Use Caution/Monitor.

            • dextromoramide

              orphenadrine and dextromoramide both increase sedation. Use Caution/Monitor.

            • diamorphine

              orphenadrine and diamorphine both increase sedation. Use Caution/Monitor.

            • diazepam

              diazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • dicyclomine

              dicyclomine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • difelikefalin

              difelikefalin and orphenadrine both increase sedation. Use Caution/Monitor.

            • difenoxin hcl

              orphenadrine and difenoxin hcl both increase sedation. Use Caution/Monitor.

            • dimenhydrinate

              dimenhydrinate and orphenadrine both increase sedation. Use Caution/Monitor.

            • diphenhydramine

              diphenhydramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              diphenhydramine and orphenadrine both increase sedation. Use Caution/Monitor.

            • diphenoxylate hcl

              orphenadrine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.

            • dipipanone

              orphenadrine and dipipanone both increase sedation. Use Caution/Monitor.

            • donepezil

              donepezil increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dopexamine

              orphenadrine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dosulepin

              orphenadrine and dosulepin both increase sedation. Use Caution/Monitor.

            • doxepin

              doxepin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and doxepin both increase sedation. Use Caution/Monitor.

            • doxylamine

              doxylamine and orphenadrine both increase sedation. Use Caution/Monitor.

            • droperidol

              orphenadrine and droperidol both increase sedation. Use Caution/Monitor.

            • echothiophate iodide

              echothiophate iodide increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • esketamine intranasal

              esketamine intranasal, orphenadrine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

            • estazolam

              estazolam and orphenadrine both increase sedation. Use Caution/Monitor.

            • ethanol

              orphenadrine and ethanol both increase sedation. Use Caution/Monitor.

            • etomidate

              etomidate and orphenadrine both increase sedation. Use Caution/Monitor.

            • fenfluramine

              orphenadrine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • fesoterodine

              fesoterodine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • finerenone

              orphenadrine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

            • flavoxate

              flavoxate and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • flibanserin

              orphenadrine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

            • fluphenazine

              orphenadrine and fluphenazine both increase sedation. Use Caution/Monitor.

            • flurazepam

              flurazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • galantamine

              galantamine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • ganaxolone

              orphenadrine and ganaxolone both increase sedation. Use Caution/Monitor.

            • glycopyrrolate

              glycopyrrolate and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • glycopyrrolate inhaled

              glycopyrrolate inhaled and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • haloperidol

              orphenadrine and haloperidol both increase sedation. Use Caution/Monitor.

            • homatropine

              homatropine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • huperzine A

              huperzine A increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • hydromorphone

              orphenadrine and hydromorphone both increase sedation. Use Caution/Monitor.

            • hydroxyzine

              hydroxyzine and orphenadrine both increase sedation. Use Caution/Monitor.

            • hyoscyamine

              hyoscyamine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • hyoscyamine spray

              hyoscyamine spray and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • iloperidone

              orphenadrine and iloperidone both increase sedation. Use Caution/Monitor.

            • imipramine

              imipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and imipramine both increase sedation. Use Caution/Monitor.

            • incobotulinumtoxinA

              orphenadrine, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

            • ipratropium

              ipratropium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • isavuconazonium sulfate

              orphenadrine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ivacaftor

              orphenadrine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

            • ketamine

              ketamine and orphenadrine both increase sedation. Use Caution/Monitor.

            • ketotifen, ophthalmic

              orphenadrine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

            • lemborexant

              orphenadrine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

            • levorphanol

              orphenadrine and levorphanol both increase sedation. Use Caution/Monitor.

            • lofepramine

              lofepramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and lofepramine both increase sedation. Use Caution/Monitor.

            • lofexidine

              orphenadrine and lofexidine both increase sedation. Use Caution/Monitor.

            • lomitapide

              orphenadrine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

            • loprazolam

              loprazolam and orphenadrine both increase sedation. Use Caution/Monitor.

            • lorazepam

              lorazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • lormetazepam

              lormetazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • loxapine inhaled

              orphenadrine and loxapine inhaled both increase sedation. Use Caution/Monitor.

            • lurasidone

              lurasidone, orphenadrine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

            • maprotiline

              maprotiline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and maprotiline both increase sedation. Use Caution/Monitor.

            • marijuana

              orphenadrine and marijuana both increase sedation. Use Caution/Monitor.

            • mavacamten

              orphenadrine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

            • meclizine

              meclizine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • melatonin

              orphenadrine and melatonin both increase sedation. Use Caution/Monitor.

            • meperidine

              orphenadrine and meperidine both increase sedation. Use Caution/Monitor.

            • meprobamate

              orphenadrine and meprobamate both increase sedation. Use Caution/Monitor.

            • metaxalone

              metaxalone and orphenadrine both increase sedation. Use Caution/Monitor.

            • methadone

              orphenadrine and methadone both increase sedation. Use Caution/Monitor.

            • methocarbamol

              methocarbamol and orphenadrine both increase sedation. Use Caution/Monitor.

            • methscopolamine

              methscopolamine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • methylenedioxymethamphetamine

              orphenadrine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • midazolam

              midazolam and orphenadrine both increase sedation. Use Caution/Monitor.

            • midazolam intranasal

              orphenadrine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.

              midazolam intranasal, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

            • mirtazapine

              orphenadrine and mirtazapine both increase sedation. Use Caution/Monitor.

            • morphine

              orphenadrine and morphine both increase sedation. Use Caution/Monitor.

            • motherwort

              orphenadrine and motherwort both increase sedation. Use Caution/Monitor.

            • moxonidine

              orphenadrine and moxonidine both increase sedation. Use Caution/Monitor.

            • nabilone

              orphenadrine and nabilone both increase sedation. Use Caution/Monitor.

            • nalbuphine

              orphenadrine and nalbuphine both increase sedation. Use Caution/Monitor.

            • neostigmine

              neostigmine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • nortriptyline

              nortriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and nortriptyline both increase sedation. Use Caution/Monitor.

            • olanzapine

              orphenadrine and olanzapine both increase sedation. Use Caution/Monitor.

            • oliceridine

              oliceridine, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

              orphenadrine increases toxicity of oliceridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Monitor for signs of urinary retention or reduced gastric motility if oliceridine is coadministered with anticholinergics.

            • onabotulinumtoxinA

              onabotulinumtoxinA and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • opium tincture

              orphenadrine and opium tincture both increase sedation. Use Caution/Monitor.

            • oxazepam

              oxazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • oxybutynin

              oxybutynin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • oxybutynin topical

              oxybutynin topical and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • oxybutynin transdermal

              oxybutynin transdermal and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • oxycodone

              orphenadrine and oxycodone both increase sedation. Use Caution/Monitor.

            • oxymorphone

              orphenadrine and oxymorphone both increase sedation. Use Caution/Monitor.

            • paliperidone

              orphenadrine and paliperidone both increase sedation. Use Caution/Monitor.

            • pancuronium

              pancuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • papaveretum

              orphenadrine and papaveretum both increase sedation. Use Caution/Monitor.

            • papaverine

              orphenadrine and papaverine both increase sedation. Use Caution/Monitor.

            • pentazocine

              orphenadrine and pentazocine both increase sedation. Use Caution/Monitor.

            • pentobarbital

              pentobarbital and orphenadrine both increase sedation. Use Caution/Monitor.

            • perphenazine

              orphenadrine and perphenazine both increase sedation. Use Caution/Monitor.

            • phenobarbital

              phenobarbital and orphenadrine both increase sedation. Use Caution/Monitor.

            • phenylephrine PO

              orphenadrine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

            • pholcodine

              orphenadrine and pholcodine both increase sedation. Use Caution/Monitor.

            • physostigmine

              physostigmine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pilocarpine

              pilocarpine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pimozide

              orphenadrine and pimozide both increase sedation. Use Caution/Monitor.

            • prabotulinumtoxinA

              orphenadrine increases effects of prabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

            • pralidoxime

              pralidoxime and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • primidone

              primidone and orphenadrine both increase sedation. Use Caution/Monitor.

            • prochlorperazine

              orphenadrine and prochlorperazine both increase sedation. Use Caution/Monitor.

            • promethazine

              promethazine and orphenadrine both increase sedation. Use Caution/Monitor.

            • propantheline

              propantheline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • propofol

              propofol and orphenadrine both increase sedation. Use Caution/Monitor.

            • propylhexedrine

              orphenadrine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • protriptyline

              protriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and protriptyline both increase sedation. Use Caution/Monitor.

            • pyridostigmine

              pyridostigmine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • quazepam

              quazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • quetiapine

              orphenadrine and quetiapine both increase sedation. Use Caution/Monitor.

            • ramelteon

              orphenadrine and ramelteon both increase sedation. Use Caution/Monitor.

            • rapacuronium

              rapacuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • remimazolam

              remimazolam, orphenadrine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.

            • risperidone

              orphenadrine and risperidone both increase sedation. Use Caution/Monitor.

            • rocuronium

              rocuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • scopolamine

              scopolamine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • scullcap

              orphenadrine and scullcap both increase sedation. Use Caution/Monitor.

            • secobarbital

              secobarbital and orphenadrine both increase sedation. Use Caution/Monitor.

            • shepherd's purse

              orphenadrine and shepherd's purse both increase sedation. Use Caution/Monitor.

            • solifenacin

              solifenacin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • stiripentol

              stiripentol, orphenadrine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

            • succinylcholine

              succinylcholine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • sufentanil

              orphenadrine and sufentanil both increase sedation. Use Caution/Monitor.

            • tapentadol

              orphenadrine and tapentadol both increase sedation. Use Caution/Monitor.

            • tazemetostat

              orphenadrine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • temazepam

              temazepam and orphenadrine both increase sedation. Use Caution/Monitor.

            • thioridazine

              orphenadrine and thioridazine both increase sedation. Use Caution/Monitor.

            • thiothixene

              orphenadrine and thiothixene both increase sedation. Use Caution/Monitor.

            • tinidazole

              orphenadrine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tiotropium

              tiotropium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • tolterodine

              tolterodine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • topiramate

              orphenadrine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

            • tramadol

              orphenadrine and tramadol both increase sedation. Use Caution/Monitor.

            • trazodone

              trazodone and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and trazodone both increase sedation. Use Caution/Monitor.

            • triazolam

              triazolam and orphenadrine both increase sedation. Use Caution/Monitor.

            • triclofos

              triclofos and orphenadrine both increase sedation. Use Caution/Monitor.

            • trifluoperazine

              orphenadrine and trifluoperazine both increase sedation. Use Caution/Monitor.

            • trihexyphenidyl

              trihexyphenidyl and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor. Potential for additive anticholinergic effects.

            • trimipramine

              trimipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

              orphenadrine and trimipramine both increase sedation. Use Caution/Monitor.

            • trospium chloride

              trospium chloride and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • vecuronium

              vecuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.

            • xylometazoline

              orphenadrine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • ziconotide

              orphenadrine and ziconotide both increase sedation. Use Caution/Monitor.

            • ziprasidone

              orphenadrine and ziprasidone both increase sedation. Use Caution/Monitor.

            • zotepine

              orphenadrine and zotepine both increase sedation. Use Caution/Monitor.

            Minor (5)

            • chlorpromazine

              orphenadrine decreases levels of chlorpromazine by unknown mechanism. Minor/Significance Unknown. Excessive anticholinergic effects and/or hypoglycemia possible.

            • eucalyptus

              orphenadrine and eucalyptus both increase sedation. Minor/Significance Unknown.

            • ruxolitinib

              orphenadrine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • ruxolitinib topical

              orphenadrine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • sage

              orphenadrine and sage both increase sedation. Minor/Significance Unknown.

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            Adverse Effects

            Frequency Not Defined

            Dry mouth

            Urinary retention

            Blurred vision, mydriasis

            Drowsiness

            Headache

            Weakness

            Increased IOP

            Palpitation

            Tachycardia

            GI disturbances

            CNS stimulation (restlessness, agitation, insomnia, mental confusion)

            Lightheadedness

            Dizziness

            Syncope

            Pruritus

            Urticarial rash

            Tremor

            Anaphylactic reactions

            Aplastic anemia

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            Warnings

            Contraindications

            Hypersensitivity

            Narrow-angle glaucoma

            Pyloric/duodenal obstruction, BPH, stenosing peptic ulcers, cardiospasm (mega-esophagus), myasthenia gravis, obstructive uropathy, paralytic ileus, ulcerative colitis, toxic megacolon, achalasia

            Cautions

            Use caution in patients with diarrhea, partial obstructive uropathy, open-angle glaucoma, cardiovascular disease, hepatic/renal impairment, thyrotoxicosis, history of drug abuse or acute alcoholism

            Some patients may experience transient episodes of light-headedness, dizziness or syncope; drug may impair ability of patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; ambulatory patients should be cautioned

            May take with food to avoid stomach upset

            Use with caution in patients with tachycardia, cardiac decompensation, coronary insufficiency, cardiac arrhythmias

            Injectable form contains sulfites, & precipitates anaphylactic-type reactions in sensitive or asthmatic individuals

            Safety of continuous long-term therapy not established; if orphenadrine is prescribed for prolonged use, periodic monitoring of blood, urine and liver function values is recommended

            Drug interaction overview

            • Confusion, anxiety and tremors have been reported in patients receiving propoxyphene and orphenadrine concomitantly; as 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
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            Pregnancy & Lactation

            Pregnancy Category: C

            Lactation: no data

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            May work through central atropine-like effect; anticholinergic activity in brain stem; has euphorigenic and analgesic properties

            Pharmacokinetics

            Half-life elimination: 14-16 hr

            Onset: 2-4 hr (peak)

            Duration: 4-6 hr

            Metabolism: Liver

            Protein binding: 20%

            Metabolites: Not fully determined (>8 metabolites)

            Excretion: urine (principally)

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            Administration

            IV/IM Administration

            Administer IM or IV injection

            IV may be given undiluted or diluted in SWI

            Give slow IV ~5 min with pt in supine position

            Patient should remain in this position for 5-10 min post-injection

            To minimize adverse reactions after parenteral administration of the drug, patient should be assisted from recumbent position

            Storage

            Store at <40°C, preferably between 15-30°C

            Protect from freezing

            Protect from light; store in tight, light-resistant containers

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            orphenadrine citrate oral
            -
            100 mg tablet
            orphenadrine citrate oral
            -
            100 mg tablet
            orphenadrine citrate oral
            -
            100 mg tablet
            orphenadrine citrate oral
            -
            100 mg tablet
            orphenadrine citrate oral
            -
            100 mg tablet
            orphenadrine citrate injection
            -
            30 mg/mL vial
            orphenadrine citrate injection
            -
            30 mg/mL vial
            orphenadrine citrate injection
            -
            30 mg/mL vial

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

            Select a drug:
            Patient Education
            orphenadrine citrate oral

            ORPHENADRINE - ORAL

            (or-FEN-uh-dreen)

            COMMON BRAND NAME(S): Norflex

            USES: Orphenadrine is used to treat muscle spasms/pain. It is usually used along with rest, physical therapy, and other treatment.

            HOW TO USE: Take this medication by mouth with or without food as directed by your doctor. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.If you are using the extended-release tablets, swallow the tablets whole. Do not crush or chew the tablets. Doing so can release all of the drug at once, increasing the risk of side effects.Tell your doctor if your condition does not improve or if it worsens.

            SIDE EFFECTS: Dry mouth, dizziness, drowsiness, lightheadedness, blurred vision, nausea, vomiting, and constipation may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.To relieve dry mouth, suck (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as confusion, anxiety, hallucinations), shaking (tremor), fast/pounding heartbeat, fainting, difficulty urinating, eye pain.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

            PRECAUTIONS: Before taking orphenadrine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: high pressure in the eye (glaucoma), stomach/intestinal/esophagus problems (such as ulcers, blockage), difficulty urinating (such as due to enlarged prostate), a certain type of muscle/nerve disease (myasthenia gravis), heart problems (such as fast/irregular heartbeat, heart failure).This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Older adults may be more sensitive to the side effects of this drug, especially confusion, drowsiness, constipation, or trouble urinating. Confusion and drowsiness can increase the risk of falling.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), other muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

            OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: unusual excitement, fast/irregular heartbeat, seizures.

            NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another condition unless your doctor directs you to do so. A different medication may be necessary in that case.If you are taking this medication for a long time, lab and/or medical tests may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

            MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

            STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

            Information last revised December 2022. Copyright(c) 2023 First Databank, Inc.

            IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.