Fenoprofen

Introduction

Generic Name: Fenoprofen
Chemical Formula: C15H14O3
Drug Class: Nonsteroidal Anti-inflammatory Drug (NSAID)
Brand names: Fenortho, Nalfon

Fenoprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is used for the treatment of mild to moderate pain, as well as inflammation associated with musculoskeletal conditions such as osteoarthritis and rheumatoid arthritis. It belongs to the propionic acid class of NSAIDs, similar to ibuprofen and naproxen, and is used for both acute and chronic pain management.

Chemical Structure and Isomerism

Fenoprofen is a propionic acid derivative, similar to other NSAIDs in its class, such as ibuprofen and naproxen. The drug is available as a racemic mixture, containing both R- and S-enantiomers.

Mechanism of Action

Like almost all of the NSAIDs, Fenoprofen works by inhibiting the activity of cyclooxygenase (COX) enzymes. These enzymes are crucial in the synthesis of prostaglandins, which are fatty compounds responsible for mediating pain, inflammation, and fever.

COX-1 Inhibition: Fenoprofen’s inhibition of COX-1 can cause a reduction in the synthesis of protective prostaglandins in the stomach and kidneys which may lead to potential side effects such as gastrointestinal irritation and nephrotoxicity.
COX-2 Inhibition: By inhibiting COX-2, fenoprofen reduces the synthesis of pro-inflammatory prostaglandins, which helps to decrease the pain, swelling, and inflammation.

Pharmacokinetics

Absorption:
After oral administration, fenoprofen is rapidly absorbed from the gastrointestinal tract. Peak plasma concentrations are typically reached within 1 to 2 hours.
Distribution:
This drug is highly bound to plasma proteins (99%), allowing it to circulate efficiently in the bloodstream and reach the sites of inflammation. It readily crosses into inflamed tissues to exert its effects.
Metabolism:
It is metabolized in the liver via oxidation and conjugation reactions. The primary metabolic pathway involves the conversion of fenoprofen to its inactive metabolites, which are then readily excreted by the kidneys.
Excretion:
The majority of the active drug and its metabolites are excreted in the urine. The elimination half-life is approximately 2 to 3 hours.

Fenoprofen Uses

Osteoarthritis and Rheumatoid Arthritis:
Fenoprofen is commonly prescribed for the management of chronic joint pain, stiffness, and inflammation associated with osteoarthritis and rheumatoid arthritis. By reducing inflammation, it improves joint function and mobility.
Acute Pain Relief:
This drug is effective in treating acute pain such as muscle strains, sprains, and other musculoskeletal injuries. It is often used in situations requiring short-term relief from pain and inflammation.
Postoperative Pain:
It is sometimes used for managing postoperative pain, particularly after minor surgeries where inflammation and pain are prominent.
Dysmenorrhea:
This drufg is also prescribed for the relief of menstrual pain (dysmenorrhea), reducing the pain associated with uterine cramping.

Dosage and Administration

For Pain and Inflammation:
- Adults: The typical dosage is 200-300 mg every 6-8 hours. The maximum daily dose should not exceed 3200 mg.

Fenoprofen is typically taken with food or milk to minimize gastrointestinal discomfort. Its relatively short half-life necessitates frequent dosing, particularly in acute pain situations.

Side Effects of Fenoprofen

Like other NSAIDs, this drug may cause side effects, particularly when used for prolonged periods or at higher doses.

Common Side Effects:
- Nausea, vomiting, or abdominal discomfort.
- Dizziness or headache.
- Diarrhea or constipation.
Serious Side Effects:
- Gastrointestinal Ulcers and Bleeding: Prolonged use can increase the risk of gastrointestinal ulcers, bleeding, and perforation.
- Kidney Impairment: Long-term use may impair the kidney function, particularly in patients with existing renal disorders.
- Cardiovascular Risk: Like other NSAIDs, prolonged use may increase the risk of heart attack or stroke, particularly in individuals with pre-existing cardiovascular diseases.

Contraindications of Fenoprofen

Fenoprofen should be avoided in the following situations:

Allergy to NSAIDs: Individuals with a history of hypersensitivity to this drug or other NSAIDs should avoid this drug due to the risk of allergic reactions.
Peptic Ulcer Disease: Patients with active gastrointestinal ulcers or a history of gastrointestinal bleeding should not take fenoprofen, as it may exaggerate these conditions.
Severe Kidney or Liver Disease: This drug is contraindicated in patients with significant renal or hepatic impairment, as its metabolism and excretion rely on these organs.
Pregnancy (Third Trimester): It is contraindicated in the third trimester of pregnancy due to the risk of fetal complications, including premature closure of the ductus arteriosus.

Drug Interactions

Fenoprofen may interact with other medications, increasing the risk of side effects or altering the effectiveness of treatment:

Anticoagulants (e.g., Warfarin): Co-administration increases the risk of bleeding.
Other NSAIDs: Combining this medicine with other NSAIDs or corticosteroids increases the likelihood of gastrointestinal and kidney-related side effects.
ACE Inhibitors and Diuretics: It may reduce the efficacy of antihypertensive medications and increase the risk of kidney damage when taken concurrently.

Warnings and Precautions

Gastrointestinal Risks: Like other NSAIDs, fenoprofen increases the risk of gastrointestinal bleeding, ulceration, and perforation, particularly with prolonged use. It should be used with caution in patients with a history of gastrointestinal disorders.
Kidney Function: Long-term use of fenoprofen may impair kidney function, especially in individuals with pre-existing renal conditions or those taking diuretics.
Cardiovascular Health: Prolonged NSAID use may increase the risk of cardiovascular events such as heart attack or stroke, particularly in patients with pre-existing cardiovascular disease.

Disclaimer

Table of Contents