Naproxen

Naproxen is a non-steroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory conditions such as rheumatoid arthritis, and fever. It is taken orally and is available in immediate-release and delayed-release formulations.

Pharmacodynamics

Naproxen acts as a non-selective coxib through reversible inhibition of both COX-1 and COX-2 enzymes. This results in inhibition of prostaglandin synthesis. Prostaglandins act as signaling molecules in the body and induce inflammation, fever, and pain. Thus, by inhibiting COX-1/2, naproxen induces anti-inflammatory, antipyretic, and analgesic effects.

Pharmacokinetics

Naproxen is highly protein-bound, with >99% of the drug bound to albumin (major plasma protein) at therapeutic concentrations. Naproxen is a substrate of CYP1A2 and CYP2C9. It is largely metabolized in the liver to 6-O-desmethylnaproxen, and both naproxen and the desmethyl metabolite are further metabolized to their respective acylglucuronide-conjugated metabolites. After metabolization, a majority of the given dose is excreted in the urine.

Drug Interactions

Naproxen may interact with antidepressants, lithium, methotrexate, probenecid, warfarin and other blood thinners, heart or blood pressure medications, including diuretics, or steroid medications such as prednisone.

NSAR wie Naproxen können die Wirksamkeit von SSRI-Antidepressiva beeinträchtigen und vermindern sowie das Blutungsrisiko erhöhen, das größer ist als das individuelle Blutungsrisiko der beiden Wirkstoffklassen, wenn sie zusammen eingenommen werden. Naproxen ist in Gegenwart von SSRIs nicht kontraindiziert, allerdings sollte die gleichzeitige Anwendung der Medikamente mit Vorsicht erfolgen.

Side effects

Common side effects include:

• Dizziness
• Headache
• bruising
• allergic reactions
• heartburn
• stomach pain.

Serious side effects include increased risk of heart disease, stroke, gastrointestinal bleeding, and stomach ulcers. The risk of heart disease may be lower than with other NSAIDs. It is not recommended in people with kidney problems. Use is not recommended in the third trimester of pregnancy.

Toxicological Data

LD50 (rat, oral): 248 mg-kg-1