Naproxen
Mechanism :
Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties. The sodium salt of naproxen has been developed as a more rapidly absorbed formulation of naproxen for use as an analgesic. The mechanism of action of the naproxen anion, like that of other NSAIDs, is not completely understood but may be related to prostaglandin synthetase inhibition.
Indication :
- Arthralgia
- Joint stiffness
- Juvenile idiopathic arthritis
- Musculoskeletal syndrome
- Pain
Contraindications :
Contraindicated in patients with known hypersensitivity to naproxen, in patients who have experienced asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs, in the treatment of peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery, in active peptic ulceration. Use with caution in renal, cardiac or hepatic impairment.
Dosing :
Oral
Juvenile idiopathic arthritis:
10-20 mg/kg in 2 divided doses. Max: 1 gm/day. In severe cases upto 15 mg/kg may be used for a few weeks.
Adverse Effect :
Gastrointestinal discomfort, abdominal pain, heartburn, nausea, diarrhea, constipation, stomatitis, occasionally bleeding and ulceration. Headache, dizziness, drowsiness, vertigo, fluid retention, light-headedness, hypersensitivity reactions like bronchospasm, rashes have been reported. Local discomfort, burning or itching and occasionally bleeding may occur with NSAID suppositories. Disturbances of blood count have been described in patients taking naproxen.
Interaction :
ACE-inhibitors: NSAIDs may diminish the antihypertensive effect of ACE-inhibitors. This interaction should be given consideration in patients taking NSAIDs concomitantly with ACE-inhibitors.
Diuretics: Can reduce the natriuretic effect-of furosemide and thiazides in some patients. This response has been attributed to inhibition of renal prostaglandin synthesis.
Lithium: When ibuprofen and lithium are administered concurrently, subjects should be observed carefully for signs of lithium toxicity.
Methotrexate: Enhances the toxicity of methotrexate. Caution should be used when NSAIDs are administered concomitantly with methotrexate.
Warfarin: Effects of warfarin and NSAIDs on GI bleeding are synergistic, such that the users of both drugs together have a risk of serious GI bleeding higher than users of either drug alone.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function, but avoid if possible |
| 10-20 | Dose as in normal renal function, but avoid if possible |
| <10 | Dose as in normal renal function, but only use if on dialysis. |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Slightly dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
| CAV/VVHD | Slightly dialysed. Dose as in GFR=10–20 mL/min |
Hepatic Dose :
Naproxen clearance is significantly decreased in patients with hepatic dysfunction. Use with caution. Do not use in severe hepatic impairment.