Loxoprofen exerts its therapeutic effects through its action on the cyclooxygenase (COX) enzymes. Its key mechanisms include:

1. Inhibition of Cyclooxygenase (COX) Enzymes:
   • Loxoprofen inhibits both COX-1 and COX-2 enzymes, which are involved in the synthesis of prostaglandins and thromboxanes.
   • COX-1 is responsible for the production of prostaglandins that protect the gastric mucosa and regulate platelet function.
   • COX-2 is induced during inflammation and is responsible for the production of prostaglandins that mediate pain, inflammation, and fever.
2. Reduction of Prostaglandin Synthesis:
   • By inhibiting COX enzymes, loxoprofen reduces the production of prostaglandins, leading to decreased inflammation, pain, and fever.
3. Antipyretic Effects:
   • Loxoprofen reduces fever by inhibiting prostaglandin synthesis in the hypothalamus, which regulates body temperature.

Loxoprofen is approved for a variety of clinical conditions, including:

1. Osteoarthritis:
   • Management of pain and inflammation associated with osteoarthritis.
2. Rheumatoid Arthritis:
   • Treatment of pain and inflammation in rheumatoid arthritis.
3. Musculoskeletal Disorders:
   • Management of pain and inflammation in conditions such as sprains, strains, and tendinitis.
4. Off-Label Uses:
   • Management of chronic pain conditions (e.g., low back pain).

Adjunctive therapy for dental pain

The dosage of loxoprofen varies depending on the indication, patient response, and tolerability. The following dosing guidelines are based on the British National Formulary (BNF) and clinical pharmacology references:

1. Adults:
   • Oral: 60 mg three times daily, not exceeding 180 mg daily.
   • Topical: Apply 1–2 g of gel to the affected area 2–3 times daily.
2. Children:
   • Oral: 1–2 mg/kg daily in divided doses, not exceeding 60 mg daily.

Important Considerations:

• Loxoprofen is available in oral tablets and topical gel formulations.
• Dose adjustments may be necessary for patients with hepatic or renal impairment.
• Loxoprofen should be taken with food or milk to minimize gastrointestinal side effects.

Loxoprofen is generally well-tolerated, but it is associated with a range of side effects, some of which can be serious. Common side effects include:

1. Gastrointestinal:
   • Nausea, vomiting, dyspepsia, and abdominal pain.
   • Gastric ulcers and gastrointestinal bleeding (rare but serious).
2. Cardiovascular:
   • Increased risk of myocardial infarction and stroke, particularly with long-term use or high doses.
3. Renal:
   • Acute kidney injury and interstitial nephritis (rare).
4. Other:
   • Headache, dizziness, and rash.

Serious Side Effects:

• Gastrointestinal Bleeding: Particularly in elderly patients or those with a history of peptic ulcer disease.
• Hypersensitivity Reactions: Stevens-Johnson syndrome (SJS) and anaphylaxis (rare).
• Hepatotoxicity: Elevated liver enzymes and, rarely, severe liver damage.

Loxoprofen requires careful monitoring and adherence to specific precautions to ensure patient safety:

1. Gastrointestinal Risk:
   • Use with caution in patients with a history of peptic ulcer disease or gastrointestinal bleeding. Consider concomitant use of a proton pump inhibitor (PPI) for gastroprotection.
2. Cardiovascular Risk:
   • Use with caution in patients with a history of cardiovascular disease. Regular monitoring of cardiovascular health is recommended.
3. Renal Impairment:
   • Use with caution in patients with impaired kidney function. Avoid use in severe renal impairment (CrCl <30 mL/min).
4. Pregnancy and Lactation:
   • Loxoprofen should be avoided during the third trimester of pregnancy due to the risk of premature closure of the ductus arteriosus. It is excreted in breast milk, so breastfeeding is generally not recommended.
5. Elderly Patients:
   • Lower doses may be required due to increased sensitivity to side effects, particularly gastrointestinal and renal.

Loxoprofen has a significant potential for drug interactions due to its effects on prostaglandin synthesis and metabolism. Key interactions include:

1. Anticoagulants:
   • Loxoprofen may enhance the anticoagulant effects of warfarin, increasing the risk of bleeding.
2. Other NSAIDs:
   • Concurrent use with other NSAIDs increases the risk of gastrointestinal side effects.
3. Antihypertensives:
   • Loxoprofen may reduce the efficacy of antihypertensive medications, such as ACE inhibitors and beta-blockers.
4. Diuretics:
   • Loxoprofen may reduce the diuretic and antihypertensive effects of diuretics.
5. Lithium:
   • Loxoprofen may increase lithium levels, increasing the risk of toxicity.

Loxoprofen is the generic name for this medication. It is marketed under various brand names, depending on the country and manufacturer. Some examples include:

• Loxonin (a well-known brand in Japan and other regions).
• Loxoprofen Accord.
• Loxoprofen Mylan.
• Loxoprofen Sandoz.