Synflex

Action

Unknown. Thought to inhibit prostaglandin synthesis.

Availability

naproxen

Oral suspension: 125 mg/5 ml

Tablets: 250 mg, 375 mg, 500 mg

Tablets (delayed-release): 375 mg, 500 mg

naproxen sodium

Caplets, tablets: 220 mg, 275 mg, 550 mg

Tablets (controlled-release): 375 mg, 500 mg, 750 mg

Indications and dosages

➣ Pain; osteoarthritis; ankylosing spondylitis; dysmenorrhea; bursitis; acute tendinitis

Adults: 250 to 500 mg (naproxen) P.O. b.i.d. (up to 1.5 g/day); 375 to 500 mg (naproxen delayed-release) P.O. t.i.d.; 250 mg, 375 mg, or 500 mg (naproxen oral suspension) P.O. b.i.d.; 275 to 550 mg (naproxen sodium) P.O. b.i.d. (up to 1.65 g/day)

Children: 10 mg/kg P.O. daily in two divided doses (naproxen only)

➣ Mild to moderate pain; primary dysmenorrhea

Adults: Initially, 500 mg (naproxen) P.O., followed by 250 mg q 6 to 8 hours p.r.n., to a maximum of 1.25 g/day. Or initially, 550 mg (naproxen sodium) P.O., followed by 275 mg q 6 to 8 hours p.r.n., to a maximum of 1,375 mg/day.

➣ Gout

Adults: Initially, 750 mg (naproxen) P.O., followed by 250 mg q 8 hours or initially, 825 mg (naproxen sodium) P.O., followed by 275 mg q 8 hours. On day 1,1,000 to 1,500 mg (naproxen sodium controlled-release formulation) P.O. once daily, followed by 1,000 mg once daily until attack has subsided.

➣ Management of pain, primary dysmenorrhea, acute tendinitis and bursitis

Adults: Initially, two 500-mg naproxen sodium controlled-release tablets P.O. once daily. Or, for patients requiring greater analgesic benefit, two 750-mg naproxen sodium controlled-release tablets P.O. once daily. Or, three 500-mg naproxen sodium controlled-release tablets may be used for a limited period. Thereafter, total daily dose shouldn't exceed two 500-mg tablets.

➣ Rheumatoid arthritis, osteoarthritis, ankylosing spondylitis

Adults: Initially, two 375-mg naproxen sodium controlled-release tablets P.O. once daily, one 750-mg tablet P.O. once daily, or two 500-mg tablets P.O. once daily. During long-term administration, adjust dosage up or down depending on patient's clinical response. Use lowest effective dose in all patients. (Patients already taking naproxen 250 mg, 375 mg, or 500 mg b.i.d. may have their total daily dosage replaced with naproxen sodium controlled-release tablets as a single daily dose.)

Dosage adjustment

• Renal or hepatic impairment

• Elderly patients

Contraindications

• Hypersensitivity to drug or other NSAIDs

• Asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs

• Perioperative pain in the setting of coronary artery bypass graft surgery

Precautions

Use cautiously in:

• severe cardiovascular, renal, or hepatic disease

• advanced renal disease (not recommended)

• history of ulcer disease or GI bleeding (use with extreme caution)

• chronic alcohol use or abuse

• elderly patients

• pregnant patients

• breastfeeding patients (avoid use)

• children (naproxen sodium controlled-release) and naproxen use in children younger than age 2 (safety not established).

Administration

• Give with food or milk to avoid GI upset.

Adverse reactions

CNS: dizziness, drowsiness, headache, vertigo, light-headedness

CV: palpitations, tachycardia, hypertension

GU: renal toxicity (with long-term use in patients in whom renal prostaglandins have a compensatory role in maintenance of renal perfusion), renal papillary necrosis

EENT: visual disturbances, tinnitus, auditory disturbances

GI: nausea, diarrhea, constipation, heartburn, abdominal pain, stomatitis, GI bleeding

Skin: rash, pruritus, skin eruptions, sweating, photosensitivity, exfoliative dermatitis, Stevens-Johnson syndrome, toxic epidermal necrolysis

Other: thirst, edema, allergic reactions including anaphylaxis

Interactions

Drug-drug. Acetaminophen (chronic use), cyclosporine: increased risk of adverse renal effects

Anticoagulants, thrombolytics: increased anticoagulant effect

Antihypertensives, cefamandole, cefoperazone, cefotetan, diuretics, eptifibatide: decreased response

Antineoplastics, methotrexate: increased risk of nephrotoxicity

Aspirin: decreased naproxen efficacy

Aspirin, corticosteroids, other NSAIDs: additive adverse GI effects

Clopidogrel, plicamycin, ticlopidine, valproic acid: increased risk of bleeding Insulin, oral hypoglycemics: increased risk of hypoglycemia

Lithium: increased lithium blood level and risk of nephrotoxicity

Other photosensitizing agents: increased risk of photosensitivity

Probenecid: increased naproxen blood level, increased risk of toxicity

Drug-diagnostic tests. Alanine amino-transferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, creatinine, lactate dehydroge-nase, potassium: increased levels

Bleeding time: prolonged for up to 4 days after therapy ends

Creatinine clearance, glucose, hematocrit, hemoglobin, leukocytes, platelets: decreased values

Urine 5-hydroxy-indoleacetic acid, urine steroids: test interference

Drug-herbs. Anise, arnica, chamomile, clove, dong quai, fenugreek, feverfew, garlic, ginger, ginkgo, ginseng, licorice: increased anticoagulant effect, increased risk of bleeding

Patient monitoring

• Monitor GI status. Stay alert for signs and symptoms of GI bleeding.

In long-term use, assess CBC with white cell differential and coagulation studies, and monitor for visual and hearing impairment and renal toxicity.

• Monitor cardiovascular status for tachycardia, palpitations, hypertension, and edema.

• Monitor blood glucose level closely in diabetic patients.

Monitor patient for signs and symptoms of serious skin manifestations; discontinue drug at first appearance of rash or other signs of hypersensitivity.

Patient teaching

• Tell patient to take medication with food or milk followed by 8 oz of water, and to stay upright for 30 minutes afterward.

• Inform patient that he may crush or break regular tablets but must swallow delayed- or controlled-release form whole.

• Tell patient that drug's full therapeutic effect may take up to 2 weeks.

• Caution patient not to exceed recommended dosage.

Instruct patient how to recognize and immediately report signs and symptoms of renal toxicity and serious skin manifestations.

• Advise patient to use sunscreen to prevent photosensitivity reaction.

• Instruct patient not to take over-the-counter medications unless prescribed.

• Tell patient to consult prescriber before taking herbs.

• Advise female patient to tell prescriber if she is pregnant or breastfeeding before starting drug.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.