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Orphenadrine, Aspirin, and Caffeine

Medically reviewed by Drugs.com. Last updated on July 6, 2020.

Pronunciation

(or FEN a dreen, AS pir in, & KAF een)

Index Terms

  • Aspirin, Caffeine, and Orphenadrine
  • Aspirin, Orphenadrine, and Caffeine
  • Caffeine, Orphenadrine, and Aspirin
  • Norgesic

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Tablet, Oral:

Norgesic Forte: Orphenadrine citrate 50 mg, aspirin 770 mg, and caffeine 60 mg

Orphengesic Forte: Orphenadrine citrate 50 mg, aspirin 770 mg, and caffeine 60 mg

Generic: Orphenadrine citrate 50 mg, aspirin 770 mg, and caffeine 60 mg

Brand Names: U.S.

  • Norgesic
  • Orphengesic Forte

Pharmacologic Category

  • Skeletal Muscle Relaxant

Pharmacology

Aspirin: Inhibits prostaglandin synthesis in the CNS and peripherally blocks pain impulse generation.

Caffeine: A CNS stimulant.

Orphenadrine: Indirect skeletal muscle relaxant thought to work by central atropine-like effects; has some euphorigenic and analgesic properties.

Use: Labeled Indications

Musculoskeletal pain: Relief of mild to moderate pain and discomfort associated with acute musculoskeletal disorders.

Contraindications

Hypersensitivity to orphenadrine, aspirin, caffeine, or any component of the formulation; glaucoma; pyloric obstruction; duodenal obstruction; achalasia; prostatic hyperplasia; bladder neck obstruction; myasthenia gravis.

Dosing: Adult

Musculoskeletal pain: Oral: Orphenadrine 50 mg/aspirin 770 mg/caffeine 60 mg per tablet: One-half to 1 tablet 3 to 4 times daily.

Dosing: Geriatric

Avoid use (Beers Criteria [AGS 2019]).

Storage

Store at ≤30°C (≤86°F).

Drug Interactions

Abametapir: May increase the serum concentration of CYP1A2 Substrates (High risk with Inhibitors). Avoid combination

Acalabrutinib: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Acebrophylline: May enhance the stimulatory effect of CNS Stimulants. Avoid combination

Acetylcholinesterase Inhibitors: May diminish the therapeutic effect of Anticholinergic Agents. Anticholinergic Agents may diminish the therapeutic effect of Acetylcholinesterase Inhibitors. Monitor therapy

Aclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Adenosine: Caffeine and Caffeine Containing Products may diminish the therapeutic effect of Adenosine. Management: Monitor for decreased effect of adenosine if patient is receiving caffeine; significantly higher adenosine doses or alternative agents may be required. Discontinue caffeine 24 hours in advance of scheduled diagnostic use of adenosine if possible. Consider therapy modification

Agents with Antiplatelet Properties (e.g., P2Y12 inhibitors, NSAIDs, SSRIs, etc.): May enhance the adverse/toxic effect of Salicylates. Increased risk of bleeding may result. Monitor therapy

Agents with Antiplatelet Properties (e.g., P2Y12 inhibitors, NSAIDs, SSRIs, etc.): May enhance the antiplatelet effect of other Agents with Antiplatelet Properties. Monitor therapy

Agents with Blood Glucose Lowering Effects: Salicylates may enhance the hypoglycemic effect of Agents with Blood Glucose Lowering Effects. Monitor therapy

Ajmaline: Salicylates may enhance the adverse/toxic effect of Ajmaline. Specifically, the risk for cholestasis may be increased. Monitor therapy

Alcohol (Ethyl): May enhance the CNS depressant effect of Orphenadrine. Avoid combination

Alendronate: Aspirin may enhance the adverse/toxic effect of Alendronate. Specifically, the incidence of upper gastrointestinal adverse events may be increased Monitor therapy

Alizapride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Amantadine: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Amifampridine: Agents With Seizure Threshold Lowering Potential may enhance the neuroexcitatory and/or seizure-potentiating effect of Amifampridine. Monitor therapy

Ammonium Chloride: May increase the serum concentration of Salicylates. Monitor therapy

Angiotensin-Converting Enzyme Inhibitors: Salicylates may enhance the nephrotoxic effect of Angiotensin-Converting Enzyme Inhibitors. Salicylates may diminish the therapeutic effect of Angiotensin-Converting Enzyme Inhibitors. Monitor therapy

Anticholinergic Agents: May enhance the adverse/toxic effect of other Anticholinergic Agents. Monitor therapy

Anticoagulants: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Anticoagulants: Salicylates may enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Apixaban: Aspirin may enhance the adverse/toxic effect of Apixaban. Specifically, the risk for bleeding may be increased. Management: Carefully consider risks and benefits of this combination and monitor closely. Consider therapy modification

AtoMOXetine: May enhance the hypertensive effect of Sympathomimetics. AtoMOXetine may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Azelastine (Nasal): May enhance the CNS depressant effect of CNS Depressants. Avoid combination

Bemiparin: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Bemiparin. Management: Avoid concomitant use of bemiparin with antiplatelet agents. If concomitant use is unavoidable, monitor closely for signs and symptoms of bleeding. Consider therapy modification

Benzbromarone: Salicylates may diminish the therapeutic effect of Benzbromarone. Monitor therapy

Botulinum Toxin-Containing Products: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Botulinum Toxin-Containing Products: Muscle Relaxants (Centrally Acting) may enhance the adverse/toxic effect of Botulinum Toxin-Containing Products. Specifically, the risk for increased muscle weakness may be enhanced. Monitor therapy

Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Broccoli: May decrease the serum concentration of CYP1A2 Substrates (High risk with Inducers). Monitor therapy

Bromopride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Bromperidol: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

BuPROPion: May enhance the neuroexcitatory and/or seizure-potentiating effect of Agents With Seizure Threshold Lowering Potential. Monitor therapy

Calcium Channel Blockers (Nondihydropyridine): May enhance the antiplatelet effect of Aspirin. Monitor therapy

Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Cannabis: May decrease the serum concentration of CYP1A2 Substrates (High risk with Inducers). Monitor therapy

Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Carbonic Anhydrase Inhibitors: Salicylates may enhance the adverse/toxic effect of Carbonic Anhydrase Inhibitors. Salicylate toxicity might be enhanced by this same combination. Management: Avoid these combinations when possible.Dichlorphenamide use with high-dose aspirin as contraindicated. If another combination is used, monitor patients closely for adverse effects. Tachypnea, anorexia, lethargy, and coma have been reported. Consider therapy modification

Cephalothin: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Cephalothin. Specifically, the risk for bleeding may be increased. Monitor therapy

Chlorphenesin Carbamate: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Cimetropium: Anticholinergic Agents may enhance the anticholinergic effect of Cimetropium. Avoid combination

CNS Depressants: May enhance the CNS depressant effect of Orphenadrine. Avoid combination

Cocaine (Topical): May enhance the hypertensive effect of Sympathomimetics. Management: Consider alternatives to use of this combination when possible. Monitor closely for substantially increased blood pressure or heart rate and for any evidence of myocardial ischemia with concurrent use. Consider therapy modification

Collagenase (Systemic): Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Collagenase (Systemic). Specifically, the risk of injection site bruising and/or bleeding may be increased. Monitor therapy

Corticosteroids (Systemic): Salicylates may enhance the adverse/toxic effect of Corticosteroids (Systemic). These specifically include gastrointestinal ulceration and bleeding. Corticosteroids (Systemic) may decrease the serum concentration of Salicylates. Withdrawal of corticosteroids may result in salicylate toxicity. Monitor therapy

CYP1A2 Inducers (Moderate): May decrease the serum concentration of Caffeine and Caffeine Containing Products. Monitor therapy

CYP1A2 Inhibitors (Moderate): May increase the serum concentration of Caffeine and Caffeine Containing Products. Monitor therapy

Dabigatran Etexilate: Aspirin may enhance the adverse/toxic effect of Dabigatran Etexilate. Specifically, the risk for bleeding may be increased. Management: Carefully consider risks and benefits of this combination and monitor closely; Canadian labeling states that low dose aspirin could be considered, but the use of antiplatelets are not recommended for stroke prevention in patients with atrial fibrillation. Consider therapy modification

Dasatinib: May enhance the anticoagulant effect of Agents with Antiplatelet Properties. Monitor therapy

Deoxycholic Acid: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Deoxycholic Acid. Specifically, the risk for bleeding or bruising in the treatment area may be increased. Monitor therapy

Dexibuprofen: Aspirin may enhance the adverse/toxic effect of Dexibuprofen. Dexibuprofen may diminish the cardioprotective effect of Aspirin. Avoid combination

Dexketoprofen: Salicylates may enhance the adverse/toxic effect of Dexketoprofen. Dexketoprofen may diminish the therapeutic effect of Salicylates. Salicylates may decrease the serum concentration of Dexketoprofen. Management: The use of high-dose salicylates (3 g/day or more in adults) together with dexketoprofen is inadvisable. Consider administering dexketoprofen 30-120 min after or at least 8 hrs before cardioprotective doses of aspirin to minimize any possible interaction. Avoid combination

Dimethindene (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Doxofylline: Caffeine and Caffeine Containing Products may enhance the adverse/toxic effect of Doxofylline. Avoid combination

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Edoxaban: Aspirin may enhance the adverse/toxic effect of Edoxaban. Specifically, the risk of bleeding may be increased. Aspirin may increase the serum concentration of Edoxaban. Management: Carefully consider the anticipated risks and benefits of this combination. If combined, increased monitoring for bleeding is recommended. Consider therapy modification

Eluxadoline: Anticholinergic Agents may enhance the constipating effect of Eluxadoline. Avoid combination

Enoxaparin: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Enoxaparin. Management: Discontinue antiplatelet agents prior to initiating enoxaparin whenever possible. If concomitant administration is unavoidable, monitor closely for signs and symptoms of bleeding. Consider therapy modification

Fat Emulsion (Fish Oil Based): May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Monitor therapy

Felbinac: May enhance the adverse/toxic effect of Aspirin. Monitor therapy

Floctafenine: May enhance the adverse/toxic effect of Aspirin. An increased risk of bleeding may be associated with use of this combination. Floctafenine may diminish the cardioprotective effect of Aspirin. Avoid combination

Formoterol: Caffeine and Caffeine Containing Products may enhance the adverse/toxic effect of Formoterol. Caffeine and Caffeine Containing Products may enhance the hypokalemic effect of Formoterol. Monitor therapy

Gastrointestinal Agents (Prokinetic): Anticholinergic Agents may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Monitor therapy

Ginkgo Biloba: May enhance the anticoagulant effect of Salicylates. Management: Consider alternatives to this combination of agents. Monitor for signs and symptoms of bleeding (especially intracranial bleeding) if salicylates are used in combination with ginkgo biloba. Consider therapy modification

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Monitor therapy

Glucosamine: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Glycopyrrolate (Oral Inhalation): Anticholinergic Agents may enhance the anticholinergic effect of Glycopyrrolate (Oral Inhalation). Avoid combination

Glycopyrronium (Topical): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Gold Sodium Thiomalate: Aspirin may enhance the adverse/toxic effect of Gold Sodium Thiomalate. Specifically, liver function tests may be elevated when these agents are combined. Monitor therapy

Guanethidine: May enhance the arrhythmogenic effect of Sympathomimetics. Guanethidine may enhance the hypertensive effect of Sympathomimetics. Monitor therapy

Heparin: Aspirin may enhance the anticoagulant effect of Heparin. Monitor therapy

Herbs (Anticoagulant/Antiplatelet Properties) (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Bleeding may occur. Management: Avoid combination when possible. If used, monitor more closely for evidence of bleeding. Discontinue herbal products with anticoagulant or antiplatelet actions 2 weeks prior to surgical, dental, or invasive procedures. Consider therapy modification

Herbs (Anticoagulant/Antiplatelet Properties) (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Salicylates. Bleeding may occur. Management: Avoid coadministration of herbs possessing anticoagulant/antiplatelet properties and salicylates. If coadministered, monitor for bleeding. Discontinue anticoagulant/antiplatelet herbs 2 weeks prior to surgical, dental or invasive procedures. Consider therapy modification

Hyaluronidase: Salicylates may diminish the therapeutic effect of Hyaluronidase. Monitor therapy

Ibritumomab Tiuxetan: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Ibritumomab Tiuxetan. Both agents may contribute to impaired platelet function and an increased risk of bleeding. Monitor therapy

Ibrutinib: May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Monitor therapy

Icosapent Ethyl: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Indacaterol: Caffeine and Caffeine Containing Products may enhance the adverse/toxic effect of Indacaterol. Caffeine and Caffeine Containing Products may enhance the hypokalemic effect of Indacaterol. Monitor therapy

Influenza Virus Vaccine (Live/Attenuated): May enhance the adverse/toxic effect of Salicylates. Specifically, Reye's syndrome may develop. Avoid combination

Inotersen: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Iohexol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iohexol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iohexol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic anticonvulsants. Consider therapy modification

Iomeprol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iomeprol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iomeprol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic anticonvulsants. Consider therapy modification

Iopamidol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iopamidol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iopamidol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic anticonvulsants. Consider therapy modification

Ipratropium (Oral Inhalation): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Itopride: Anticholinergic Agents may diminish the therapeutic effect of Itopride. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Ketorolac (Nasal): May enhance the adverse/toxic effect of Aspirin. An increased risk of bleeding may be associated with use of this combination. Ketorolac (Nasal) may diminish the cardioprotective effect of Aspirin. Avoid combination

Ketorolac (Systemic): May enhance the adverse/toxic effect of Aspirin. An increased risk of bleeding may be associated with use of this combination. Ketorolac (Systemic) may diminish the cardioprotective effect of Aspirin. Avoid combination

Lesinurad: Aspirin may diminish the therapeutic effect of Lesinurad. Monitor therapy

Levosulpiride: Anticholinergic Agents may diminish the therapeutic effect of Levosulpiride. Avoid combination

Limaprost: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Linezolid: May enhance the hypertensive effect of Sympathomimetics. Management: Reduce initial doses of sympathomimetic agents, and closely monitor for enhanced pressor response, in patients receiving linezolid. Specific dose adjustment recommendations are not presently available. Consider therapy modification

Lisuride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Lithium: Caffeine and Caffeine Containing Products may decrease the serum concentration of Lithium. Monitor therapy

Lofexidine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Loop Diuretics: Salicylates may diminish the diuretic effect of Loop Diuretics. Loop Diuretics may increase the serum concentration of Salicylates. Monitor therapy

Macimorelin: Aspirin may diminish the diagnostic effect of Macimorelin. Avoid combination

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Methotrexate: Salicylates may increase the serum concentration of Methotrexate. Salicylate doses used for prophylaxis of cardiovascular events are not likely to be of concern. Management: Consider avoiding coadministration of methotrexate and salicylates. If coadministration cannot be avoided, monitor for increased toxic effects of methotrexate. Salicylate doses used for prophylaxis of cardiovascular events are not likely to be of concern. Consider therapy modification

Metoclopramide: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy

Minocycline (Systemic): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mirabegron: Anticholinergic Agents may enhance the adverse/toxic effect of Mirabegron. Monitor therapy

Multivitamins/Fluoride (with ADE): May enhance the antiplatelet effect of Aspirin. Aspirin may decrease the serum concentration of Multivitamins/Fluoride (with ADE). Specifically, aspirin may decrease the absorption of ascorbic acid. Monitor therapy

Multivitamins/Minerals (with ADEK, Folate, Iron): May enhance the antiplatelet effect of Aspirin. Aspirin may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, aspirin may decrease absorption of ascorbic acid. Monitor therapy

Multivitamins/Minerals (with AE, No Iron): May enhance the antiplatelet effect of Aspirin. Aspirin may decrease the serum concentration of Multivitamins/Minerals (with AE, No Iron). Specifically, aspirin may decrease the absorption of ascorbic acid. Monitor therapy

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Nicorandil: Aspirin may enhance the adverse/toxic effect of Nicorandil. Specifically, the risk of gastrointestinal ulceration and hemorrhage may be increased. Monitor therapy

Nitroglycerin: Anticholinergic Agents may decrease the absorption of Nitroglycerin. Specifically, anticholinergic agents may decrease the dissolution of sublingual nitroglycerin tablets, possibly impairing or slowing nitroglycerin absorption. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents (COX-2 Selective): Aspirin may enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents (COX-2 Selective). Management: Concurrent use of aspirin at doses beyond cardioprotective levels is not recommended. While concurrent use of low-dose aspirin with a COX-2 inhibitor is permissable, patients should be monitored closely for signs/symptoms of GI ulceration/bleeding. Consider therapy modification

Nonsteroidal Anti-Inflammatory Agents (Nonselective): May enhance the adverse/toxic effect of Salicylates. An increased risk of bleeding may be associated with use of this combination. Nonsteroidal Anti-Inflammatory Agents (Nonselective) may diminish the cardioprotective effect of Salicylates. Salicylates may decrease the serum concentration of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Management: Nonselective NSAIDs may reduce aspirin's cardioprotective effects. Administer ibuprofen 30-120 minutes after immediate-release aspirin, 2 to 4 hours after extended-release aspirin, or 8 hours before aspirin. Consider therapy modification

Nonsteroidal Anti-Inflammatory Agents (Topical): May enhance the adverse/toxic effect of Salicylates. Specifically, the risk of gastrointestinal (GI) toxicity is increased. Management: Coadministration of salicylates and topical NSAIDs is not recommended. If salicylates and topical NSAIDs are coadministered, ensure the benefits outweigh the risks and monitor for increased NSAID toxicities. Consider therapy modification

Norfloxacin: May increase the serum concentration of Caffeine and Caffeine Containing Products. Monitor therapy

Obinutuzumab: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Obinutuzumab. Specifically, the risk of serious bleeding-related events may be increased. Monitor therapy

Olodaterol: Caffeine and Caffeine Containing Products may enhance the adverse/toxic effect of Olodaterol. Caffeine and Caffeine Containing Products may enhance the hypokalemic effect of Olodaterol. Monitor therapy

Omacetaxine: Aspirin may enhance the adverse/toxic effect of Omacetaxine. Specifically, the risk for bleeding-related events may be increased. Management: Avoid concurrent use of aspirin with omacetaxine in patients with a platelet count of less than 50,000/uL. Avoid combination

Omega-3 Fatty Acids: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Oxatomide: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Oxomemazine: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

Ozanimod: May enhance the hypertensive effect of Sympathomimetics. Management: Concomitant use of ozanimod with sympathomimetic agents is not recommended. If combined, monitor patients closely for the development of hypertension, including hypertensive crises. Consider therapy modification

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

Pentosan Polysulfate Sodium: May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Specifically, the risk of bleeding may be increased by concurrent use of these agents. Monitor therapy

Pentoxifylline: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Pipemidic Acid: May increase the serum concentration of Caffeine and Caffeine Containing Products. Monitor therapy

Piribedil: CNS Depressants may enhance the CNS depressant effect of Piribedil. Monitor therapy

Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Avoid combination

Potassium Citrate: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Citrate. Avoid combination

Potassium Phosphate: May increase the serum concentration of Salicylates. Monitor therapy

PRALAtrexate: Salicylates may increase the serum concentration of PRALAtrexate. Salicylate doses used for prophylaxis of cardiovascular events are unlikely to be of concern. Management: Consider avoiding concomitant use of salicylates and pralatrexate. If coadministered, monitor for increased pralatrexate adverse effects. Salicylate doses used for prophylaxis of cardiovascular events are not likely to be of concern. Consider therapy modification

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Avoid combination

Probenecid: Salicylates may diminish the therapeutic effect of Probenecid. Monitor therapy

Prostacyclin Analogues: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Ramosetron: Anticholinergic Agents may enhance the constipating effect of Ramosetron. Monitor therapy

Regadenoson: Caffeine and Caffeine Containing Products may diminish the vasodilatory effect of Regadenoson. Management: Avoiding using caffeine or other methylxanthine containing products (e.g., theophylline) for at least 12 hours prior to the administration of regadenoson. Consider therapy modification

Revefenacin: Anticholinergic Agents may enhance the anticholinergic effect of Revefenacin. Avoid combination

Rivaroxaban: Aspirin may enhance the adverse/toxic effect of Rivaroxaban. Specifically, the risk of bleeding may be increased. Management: Carefully consider risks and benefits of this combination and monitor closely. Consider therapy modification

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Salicylates: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Salicylates. Increased risk of bleeding may result. Monitor therapy

Salicylates: May enhance the anticoagulant effect of other Salicylates. Monitor therapy

Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Management: Avoid concomitant use of anticholinergic agents and secretin. Discontinue anticholinergic agents at least 5 half-lives prior to administration of secretin. Consider therapy modification

Selective Serotonin Reuptake Inhibitors: May enhance the antiplatelet effect of Aspirin. Monitor therapy

Selumetinib: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Serotonin/Norepinephrine Reuptake Inhibitors: May enhance the antiplatelet effect of Aspirin. Monitor therapy

Sincalide: Drugs that Affect Gallbladder Function may diminish the therapeutic effect of Sincalide. Management: Consider discontinuing drugs that may affect gallbladder motility prior to the use of sincalide to stimulate gallbladder contraction. Consider therapy modification

Solriamfetol: Sympathomimetics may enhance the hypertensive effect of Solriamfetol. Sympathomimetics may enhance the tachycardic effect of Solriamfetol. Monitor therapy

Solriamfetol: CNS Stimulants may enhance the hypertensive effect of Solriamfetol. CNS Stimulants may enhance the tachycardic effect of Solriamfetol. Monitor therapy

Spironolactone: Aspirin may diminish the therapeutic effect of Spironolactone. Monitor therapy

Stiripentol: May increase the serum concentration of Caffeine and Caffeine Containing Products. Avoid combination

Sucroferric Oxyhydroxide: May decrease the serum concentration of Aspirin. Management: Administer aspirin at least 1 hour before administration of sucroferric oxyhydroxide. Consider therapy modification

Sulfinpyrazone: Salicylates may decrease the serum concentration of Sulfinpyrazone. Avoid combination

Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Monitor therapy

Talniflumate: Aspirin may enhance the adverse/toxic effect of Talniflumate. Management: When possible, consider alternatives to this combination. Concurrent use is generally not recommended. Consider therapy modification

Tedizolid: May enhance the hypertensive effect of Sympathomimetics. Tedizolid may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Tetrahydrocannabinol and Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Theophylline Derivatives: CYP1A2 Inhibitors (Weak) may increase the serum concentration of Theophylline Derivatives. Monitor therapy

Thiazide and Thiazide-Like Diuretics: Anticholinergic Agents may increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Thrombolytic Agents: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Thrombolytic Agents. Monitor therapy

Thrombolytic Agents: Salicylates may enhance the adverse/toxic effect of Thrombolytic Agents. An increased risk of bleeding may occur. Monitor therapy

Ticagrelor: Aspirin may enhance the antiplatelet effect of Ticagrelor. Aspirin may diminish the therapeutic effect of Ticagrelor. More specifically, the benefits of ticagrelor relative to clopidogrel may be diminished in adult patients receiving daily aspirin doses greater than 100-150 mg daily. Management: Avoid daily aspirin doses greater than 100 mg in adults receiving ticagrelor. Canadian recommendations are to avoid adult daily aspirin doses greater than 150 mg. Daily low-dose aspirin (U.S.: 75-100 mg; Canada: 75-150 mg) is recommended. Consider therapy modification

Tiludronate: Aspirin may decrease the serum concentration of Tiludronate. Monitor therapy

Tiotropium: Anticholinergic Agents may enhance the anticholinergic effect of Tiotropium. Avoid combination

Tipranavir: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Tobacco (Smoked): May decrease the serum concentration of Caffeine and Caffeine Containing Products. Monitor therapy

Tolperisone: May enhance the adverse/toxic effect of Muscle Relaxants (Centrally Acting). Management: Monitor for increased sedation or CNS effects if tolperisone is combined with other centrally acting muscle relaxants. Consider decreasing the tolperisone dose if these agents are combined. Consider therapy modification

Umeclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Urokinase: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Urokinase. Avoid combination

Valproate Products: Salicylates may increase the serum concentration of Valproate Products. Monitor therapy

Varicella Virus-Containing Vaccines: Salicylates may enhance the adverse/toxic effect of Varicella Virus-Containing Vaccines. Specifically, the risk for Reye's syndrome may increase. Avoid combination

Vitamin E (Systemic): May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Salicylates may enhance the anticoagulant effect of Vitamin K Antagonists. Management: Avoid as needed use of salicylates in patients taking vitamin K antagonists. Aspirin (80 to 325 mg/day) may be used with warfarin for prevention of cardiovascular events. If coadministering salicylates and vitamin K antagonists, monitor for bledding. Consider therapy modification

Zanubrutinib: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.

Also see individual agents.

Frequency not defined:

Cardiovascular: Palpitations, syncope, tachycardia

Dermatologic: Dermatologic disorder (rare), urticaria (rare)

Gastrointestinal: Constipation, gastrointestinal hemorrhage (rare), nausea, vomiting, xerostomia

Genitourinary: Urinary hesitancy, urinary retention

Nervous system: Confusion (older adults), dizziness, drowsiness, hallucination, headache, mild central nervous system stimulation

Neuromuscular & skeletal: Asthenia

Ophthalmic: Blurred vision, increased intraocular pressure, mydriasis

Postmarketing: Hematologic & oncologic: Aplastic anemia

Warnings/Precautions

Concerns related to adverse effects:

• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery, driving).

• Salicylate sensitivity: Patients with sensitivity to tartrazine dyes, nasal polyps, and asthma may have an increased risk of salicylate sensitivity.

Disease-related concerns:

• Bleeding disorders: Use aspirin with caution in patients with platelet and bleeding disorders.

• Cardiovascular disease: Use orphenadrine with caution in patients with heart failure, cardiac decompensation, coronary insufficiency, tachycardia, or cardiac arrhythmias.

• Drug abuse: Use orphenadrine with caution in patients with a history of drug abuse or acute alcoholism; euphoria may occur at therapeutic doses and the potential for abuse exists.

• GI disease: Use aspirin with caution in patients with active peptic ulcer disease.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Pediatric: Children and teenagers who have or are recovering from chickenpox or flu-like symptoms should not use this product. Changes in behavior (along with nausea and vomiting) may be an early sign of Reye's syndrome; patients should be instructed to contact their health care provider if these occur.

Other warnings/precautions:

• Appropriate use: To be used as an adjunct to rest, physical therapy, and other modes for relief of pain associated with acute musculoskeletal conditions.

• Long-term use: Has not been evaluated for continuous long-term use; monitor closely.

Monitoring Parameters

CBC, renal, and LFTs with prolonged use.

Pregnancy Considerations

Refer to individual monographs.

Patient Education

What is this drug used for?

• It is used to relax muscles.

• This drug is used with rest, PT (physical therapy), pain drugs, and other therapies.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Feeling sleepy

• Upset stomach or throwing up

• Dry mouth

• Headache

• Constipation.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Bleeding like throwing up or coughing up blood; vomit that looks like coffee grounds; blood in the urine; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a cause or that get bigger; or bleeding you cannot stop

• Feeling confused

• Very nervous and excitable

• Hallucinations (seeing or hearing things that are not there)

• Ringing in ears

• Feeling very tired or weak

• Fast or abnormal heartbeat

• Trouble passing urine

• Change in eyesight

• Very bad dizziness or passing out

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.