Prexan - General Information
An anti-inflammatory agent with analgesic and antipyretic properties. Both the acid and its sodium salt are used in the treatment of rheumatoid arthritis and other rheumatic or musculoskeletal disorders, dysmenorrhea, and acute gout. [PubChem]
Pharmacology of Prexan
Prexan is a member of the arylacetic acid group of nonsteroidal anti-inflammatory drugs (NSAIDs). Prexan has analgesic and antipyretic properties. As with other NSAIDs, its mode of action is not fully understood; however, its ability to inhibit prostaglandin synthesis may be involved in the anti-inflammatory effect.
Prexan for patients
Naprelan® (naproxen sodium controlled-release tablets) represents the first prescription product to offer convenient once-a-day dosing of naproxen, a medication long considered a standard in arthritis treatment. Naproxen or naproxen sodium-based products account for nearly one in every five prescriptions written for non-steroidal anti-inflammatory drugs (NSAID) in the United States. (Naproxen sodium, a sodium salt formulation of naproxen,
provides for more rapid absorption.)
Naprelan tablets use a proprietary delivery system IPDAS™, (Intestinal Protective Drug Absorption System), a matrix of naproxen sodium with immediate and controlled-release components. Upon ingestion, and after rapid disintegration of the tablet matrix, an initial portion (approximately 30%) of the medication is released for rapid systemic absorption -- achieving onset of analgesic action within 30 minutes. In addition, a sustained-release component of microparticles provides an extended absorption phase that has wide GI dispersion, allowing gradual absorption throughout the GI tract, and prolongs therapeutic systemic levels of the drug, enabling 24-hour duration of action and once-a-day dosing.
Naproxen has been used safely and effectively worldwide for 20 years and is one of the NSAIDs most widely used in the treatment of osteoarthritis and rheumatoid arthritis. Numerous clinical studies have demonstrated the efficacy and safety profile of naproxen. Naprelan offers the same efficacy and safety profile with the added advantage of once-a-day dosing. The most frequent complaints relate to the gastrointestinal tract. Serious GI toxicity, such as perforation, ulceration or bleeding can occur in patients treated chronically with NSAID therapy. Please consult with your physician to see if Naprelan may be right for you.
- Naprelan® is marketed by Wyeth-Ayerst Labratories and not associated with Syntex Puerto Rico, Inc.
- Naproxen is a registered trademark of Syntex Puerto Rico, Inc.
- IPDAS™ is a trademark of élan pharma ltd.
- Naprelan® (naproxen sodium) Controlled Release Tablets
Equivalent to 375 mg and 500 mg naproxen
The use of NSAIDs in patients who are receiving ACE inhibitors may potentiate renal disease states.
In vitro studies have shown that naproxen anion, because of its affinity for protein, may displace from their binding sites other drugs which are also albumin-bound.
Theoretically, the naproxen anion itself could likewise be displaced. Short-term controlled studies failed to show that taking the drug significantly affects prothrombin times when administered to individuals on coumarin-type anticoagulants. Caution is advised nonetheless, since interactions have been seen with other nonsteroidal agents of this class. Similarly, patients receiving the drug and a hydantoin, sulfonamide or sulfonylurea should be observed for signs of toxicity to these drugs.
Concomitant administration of naproxen and aspirin is not recommended because naproxen is displaced from its binding sites during the concomitant administration of aspirin, resulting in lower plasma concentrations and peak plasma levels.
The natriuretic effect of furosemide has been reported to be inhibited by some drugs of this class. Inhibition of renal lithium clearance leading to increases in plasma lithium concentrations has also been reported. Naproxen and other NSAIDs can reduce the antihypertensive effect of propranolol and other beta-blockers.
Probenecid given concurrently increases naproxen anion plasma levels and extends its plasma half-life significantly.
Caution should be used if naproxen is administered concomitantly with methotrexate. Naproxen, naproxen sodium and other NSAIDs have been reported to reduce the tubular secretion of methotrexate in an animal model, possibly increasing the toxicity of methotrexate.
Drug/Laboratory Test Interactions
Naproxen may decrease platelet aggregation and prolong bleeding time. This effect should be kept in mind when bleeding times are determined. The administration of naproxen may result in increased urinary values for 17-ketogenic steroids because of an interaction between the drug and/or its metabolites with m-dinitrobenzene used in this assay. Although 17-hydroxy-corticosteroid measurements (Porter-Silber test) do not appear to be artifactually altered, it is suggested that therapy with naproxen be temporarily discontinued 72 hours before adrenal function tests are performed if the Porter-Silber test is to be used.
Naproxen may interfere with some urinary assays of 5-hydroxy indoleacetic acid (5HIAA).
All naproxen products are contraindicated in patients who have had allergic reactions to prescription as well as to over-the-counter products containing naproxen. Anaphylactoid reactions may occur in patients without previous known exposure or hypersensitivity to aspirin, naproxen, or other NSAIDs, or in individuals with a history of angioedema, urticaria, bronchospastic reactivity (e.g. asthma), and nasal polyps. Anaphylactoid reactions, like anaphylaxis, may have a fatal outcome. Therefore, careful questioning of patients for such things as asthma, nasal polyps, urticaria, and hypotension associated with NSAIDs before starting therapy is important. In addition, if such symptoms occur during therapy, treatment with Naprelan should be discontinued.
Additional information about Prexan
Prexan Indication: For the treatment of rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, tendinitis, bursitis, and acute gout. Also for the relief of mild to moderate pain and the treatment of primary dysmenorrhea.
Mechanism Of Action: The mechanism of action of naproxen, like that of other NSAIDs, is believed to be associated with the inhibition of cyclooxygenase activity. Two unique cyclooxygenases have been described in mammals. The constitutive cyclooxygenase, COX-1, synthesizes prostaglandins necessary for normal gastrointestinal and renal function. The inducible cyclooxygenase, COX-2, generates prostaglandins involved in inflammation. Inhibition of COX-1 is thought to be associated with gastrointestinal and renal toxicity while inhibition of COX-2 provides anti-inflammatory activity.
Drug Interactions: Alendronate Increased risk of gastric toxicity
Methotrexate The NSAID increases the effect and toxicity of methotrexate
Anisindione The NSAID increases the anticoagulant effect
Dicumarol The NSAID increases the anticoagulant effect
Acenocoumarol The NSAID increases the anticoagulant effect
Warfarin The NSAID increases the anticoagulant effect
Lithium The NSAID increases serum levels of lithium
Cyclosporine Monitor for nephrotoxicity
Food Interactions: Avoid alcohol.
Take with food.
Take with a full glass of water.
Generic Name: Naproxen
Synonyms: Not Available
Drug Category: Anti-Inflammatory Agents, Non-Steroidal; Cyclooxygenase Inhibitors; Gout Suppressants
Drug Type: Small Molecule; Approved
Absorption: Naproxen itself is rapidly and completely absorbed from the GI tract with an in vivo bioavailability of 95%. Although naproxen itself is well absorbed, the sodium salt form is more rapidly absorbed resulting in higher peak plasma levels for a given dose. Food causes a slight decrease in the rate absorption.
Toxicity (Overdose): ORAL (LD50): Acute: 248 mg/kg [Rat]. 360 mg/kg [Mouse]. Symptoms of overdose include drowsiness, heartburn, indigestion, nausea, and vomiting.
Protein Binding: At therapeutic levels naproxen is greater than 99% albumin-bound.
Biotransformation: Naproxen is extensively metabolized to 6-0-desmethyl naproxen and both parent and metabolites do not induce metabolizing enzymes.
Half Life: The observed terminal elimination half-life is approximately 15 hours.
Dosage Forms of Prexan: Tablet, extended release Oral
Tablet, coated Oral
Chemical IUPAC Name: 2-(6-methoxynaphthalen-2-yl)propanoic acid
Chemical Formula: C14H14O3
Naproxen on Wikipedia: https://en.wikipedia.org/wiki/Naproxen
Organisms Affected: Humans and other mammals