NAPROSYN (naproxen) tablets, EC-NAPROSYN (naproxen) delayed-release tablets and ANAPROX DS (naproxen sodium) tablets are nonsteroidal anti-inflammatory drugs available as follows: NAPROSYN tablets are available as yellow tablets containing 500 mg of naproxen for oral administration.
EC-NAPROSYN delayed-release tablets are available as enteric-coated white tablets containing 375 mg of naproxen or 500 mg of naproxen for oral administration.
ANAPROX DS tablets are available as dark blue tablets containing 550 mg of naproxen sodium for oral administration.
Naproxen is a propionic acid derivative related to the arylacetic acid group of nonsteroidal anti-inflammatory drugs. The chemical names for naproxen and naproxen sodium are (S)-6-methoxy-α-methyl-2-naphthaleneacetic acid and (S)-6methoxy-α-methyl-2-naphthaleneacetic acid, sodium salt, respectively. Naproxen has a molecular weight of 230.26 and a molecular formula of C14H14O3. Naproxen sodium has a molecular weight of 252.23 and a molecular formula of C14H13NaO3.
Naproxen is an odorless, white to off-white crystalline substance. It is lipid-soluble, practically insoluble in water at low pH and freely soluble in water at high pH. The octanol/water partition coefficient of naproxen at pH 7.4 is 1.6 to 1.8. Naproxen sodium is a white to creamy white, crystalline solid, freely soluble in water at neutral pH.
The inactive ingredients in NAPROSYN tablets include: croscarmellose sodium, iron oxides, povidone and magnesium stearate.
The inactive ingredients in EC-NAPROSYN delayed release tablets include: croscarmellose sodium, povidone and magnesium stearate. The enteric coating dispersion contains methacrylic acid copolymer, talc, triethyl citrate, sodium hydroxide and purified water. The imprinting on the tablets is black ink. The dissolution of this enteric-coated naproxen tablet is pH dependent with rapid dissolution above pH 6. There is no dissolution below pH 4.
The inactive ingredients in ANAPROX DS tablets include: magnesium stearate, microcrystalline cellulose, povidone and talc. The coating suspension may contain hydroxypropyl methylcellulose 2910, Opaspray K-1-4227, polyethylene glycol 8000 or Opadry YS-1-4216.
DOSAGE AND ADMINISTRATION
General Dosing Instructions
Carefully consider the potential benefits and risks of NAPROSYN Tablets, EC-NAPROSYN and ANAPROX DS and other treatment options before deciding to use NAPROSYN Tablets, EC-NAPROSYN and ANAPROX DS. Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals [see WARNINGS AND PRECAUTIONS].
After observing the response to initial therapy with NAPROSYN Tablets, EC-NAPROSYN or ANAPROX DS, the dose and frequency should be adjusted to suit an individual patient’s needs.
To maintain the integrity of the enteric coating, the EC-NAPROSYN tablet should not be broken, crushed or chewed during ingestion.
Naproxen-containing products such as NAPROSYN, EC-NAPROSYN and ANAPROX DS, and other naproxen products should not be used concomitantly since they all circulate in the plasma as the naproxen anion.
Rheumatoid Arthritis, Osteoarthritis And Ankylosing Spondylitis
The recommended dosages of NAPROSYN Tablets, ANAPROX DS, and EC-NAPROSYN are shown in Table 1.
During long-term administration, the dose of naproxen may be adjusted up or down depending on the clinical response of the patient. A lower daily dose may suffice for long-term administration. The morning and evening doses do not have to be equal in size and the administration of the drug more frequently than twice daily is not necessary.
The morning and evening doses do not have to be equal in size and administration of the drug more frequently than twice daily does not generally make a difference in response.
In patients who tolerate lower doses well, the dose may be increased to naproxen 1500 mg/day for limited periods of up to 6 months when a higher level of anti-inflammatory/analgesic activity is required. When treating such patients with naproxen 1500 mg/day, the physician should observe sufficient increased clinical benefits to offset the potential increased risk.
Polyarticular Juvenile Idiopathic Arthritis
Naproxen solid-oral dosage forms may not allow for the flexible dose titration needed in pediatric patients with polyarticular juvenile idiopathic arthritis. A liquid formulation may be more appropriate for weight-based dosing and due to the need for dose flexibility in children.
In pediatric patients, doses of 5 mg/kg/day produced plasma levels of naproxen similar to those seen in adults taking 500 mg of naproxen [see CLINICAL PHARMACOLOGY]. The recommended total daily dose of naproxen is approximately 10 mg/kg given in 2 divided doses. Dosing with NAPROSYN Tablets is not appropriate for children weighing less than 50 kilograms.
Management Of Pain, Primary Dysmenorrhea, And Acute Tendonitis And Bursitis
The recommended starting dose of ANAPROX DS (naproxen sodium) tablets is 550 mg followed by 550 mg every 12 hours or 275 mg (one half of a 550 mg tablet) every 6 to 8 hours as required. The initial total daily dose should not exceed 1375 mg (two and one-half tablets) of naproxen sodium. Thereafter, the total daily dose should not exceed 1100 mg of naproxen sodium. Because the sodium salt of naproxen is more rapidly absorbed, ANAPROX DS is recommended for the management of acute painful conditions when prompt onset of pain relief is desired. NAPROSYN Tablets may also be used. The recommended starting dose of NAPROSYN Tablets is 500 mg followed by 250 mg (one half of a 500 mg NAPROSYN tablet) every 6-8 hours as required.. The total daily dose should not exceed 1250 mg of naproxen.
EC-NAPROSYN is not recommended for initial treatment of acute pain because absorption of naproxen is delayed compared to other naproxen-containing products.
The recommended starting dose is 750 mg (one and one-half tablets) of NAPROSYN Tablets followed by 250 mg (one-half tablet) every 8 hours until the attack has subsided. ANAPROX DS may also be used at a starting dose of 825 mg (one and one-half tablets) followed by 275 mg (one-half tablet) every 8 hours. EC-NAPROSYN is not recommended because of the delay in absorption.