Naproxen

BRAND NAMES:

Aleve- It contains the active ingredients of Naproxen sodium. It is available in tablets and capsules to treat pain relievers and fever reducer.

Anaprox DS – It contains the active ingredient of naproxen sodium. It is available in the form of a tablet.

EC Naprosyn - It contains the active ingredients of Naproxen sodium. It is available in the form of delayed-release tablets.

Naprelan – It contains the active ingredient of Naproxen Sodium. It is available in the form of controlled-release tablets.

Naprosyn – It contains the active ingredients of Naproxen Sodium. It is available in tablets and oral suspensions to treat anti-inflammatories and analgesics.

MECHANISM OF ACTION:

With its competitive inhibition of COX-1 and COX-2, cyclooxygenase isoenzymes, naproxen prevents arachidonic binding and produces analgesic and anti-inflammatory actions. The first phase in the synthesis of prostaglandins and thromboxane, which is crucial in fast physiological reactions, is catalyzed by COX-1 and COX-2. While COX-2 is only present in specific tumors like colon and prostate cancers, it is constitutively expressed in most tissues, including the brain, kidney, bones, and reproductive systems. In addition to producing prostaglandins in response to hormones in the bloodstream, COX-1 is in charge of preserving hemostasis, renal function, and stomach mucosal integrity. Numerous cells can induce COX-2 in response to particular inflammatory stimuli.

PHARMACOKINETICS:

Absorption: Naproxen is quickly and thoroughly absorbed when taken orally or rectally. Food can cause a delay in the absorption of orally administered naproxen, but it does not affect the amount absorbed.

Distribution: The apparent volume of distribution of Naproxen is 0.16L/Kg.

Metabolism: Phase I and Phase II metabolism of naproxen are two of the several metabolic processes that occur in the liver. CYP 1A2, 2C8, and 2C9 demethylate naproxen in the first step. Phase II metabolism occurs in both naproxen and desmethyl naproxen; desmethyl naproxen may create acyl and phenolic glucuronide metabolites, whereas naproxen can only produce acetyl glucuronide.

Excretion: After oral dosing, approximately 95% of naproxen and its metabolites can be recovered in urine. Less than 5% of naproxen is eliminated in the feces.

PHARMACODYNAMICS:

Naproxen's pharmacological impact may be related to its inhibition of cyclo-oxygenase, which reduces prostaglandin production in a range of tissues and fluids, including synovial fluid, stomach mucosa, and blood.

DOSAGE AND ADMINISTRATION:

Naproxen is available in four different forms: regulatory tablets, delayed-release tablets, extended-release tablets, and oral suspensions. The extended-release pills are typically used once per day. For gout, the pills and suspension are frequently given every 8 hours, with pain relief taking place every 6 to 8 hours. If you use naproxen daily, make sure you take it at the same time every day.

• Oral tablets – 220mg, 250mg, 275 mg, 375 mg, 500mg and 550mg
• Delayed release oral tablets – 375mg, 500mg, 750mg
• Oral capsules – 220mg
• Oral suspension – 125mg/ml

DRUG INTERACTIONS:

Drug interactions with naproxen may include 

• Pain relievers: ibuprofen, diclofenac, paracetamol, and aspirin. 
• Propranolol, enalapril, losartan, candesartan, and eprosartan are medications used to decrease high blood pressure. 
• Diuretics: furosemide 
• Blood thinners—heparin, warfarin, and clopidogrel 
• Medicines that treat diabetes- glimepiride or glipizide 
• antibiotic-moxifloxacin with ciprofloxacin 
• Zidovudine - HIV medication.

CONTRAINDICATIONS:

Hypersensitivity to naproxen or other H2- receptor antagonist.

Absolute contraindications – aspirin allergy, perioperative pain in the setting of coronary artery bypass graft surgery.

Relative contraindications- bleeding disorders, delayed esophageal transit, hepatic disease, peptic ulcer, renal impairment, stomatitis, late pregnancy.

SIDE EFFECTS:

Naproxen may cause side effects

• Constipation
• Excessive thirst
• Headache
• Dizziness
• Drowsiness
• Difficult asleep
• Burning legs
• Cold symptoms
• Hearing problems

Some serious side effects can be serious

• Changes in vision 
• Unexplained weight gain 
• Shortness of breath
• Sore throat
• Blisters
• Rash
• Itching
• Hives
• Hoarseness
• Excessive tiredness
• Nausea
• Diarrhea
• Yellowing of the skin
• Flu-like symptoms
• Fast heartbeat 
• Back pain
• Loss of appetite
• confusion

OVERDOSE:

Symptoms of overdose may include

• Extreme tiredness
• Drowsiness
• Stomach pain
• Heartburn
• Nausea
• Vomiting
• Slow breathing

TOXICITY:

Naproxen overdose has no known cure, but with the right supportive treatment, symptoms usually go away. In the first two trimesters of pregnancy, naproxen is categorized as category B, and in the third trimester, category D.