From the Research
Mefenamic acid is the longer-acting NSAID compared to diclofenac. Mefenamic acid has a half-life of approximately 2-4 hours, while diclofenac has a shorter half-life of about 1-2 hours, as noted in a study from 1. This means mefenamic acid stays in the system longer and typically requires less frequent dosing. Mefenamic acid is usually dosed three times daily (every 6-8 hours), whereas diclofenac may need to be taken more frequently depending on the formulation. However, it's essential to consider that despite its shorter half-life, diclofenac is available in extended-release formulations that can provide longer duration of action, as discussed in a review from 2. The longer half-life of mefenamic acid is due to its chemical structure and metabolism in the liver. Both medications work by inhibiting cyclooxygenase enzymes to reduce inflammation and pain, but they differ in their pharmacokinetic properties, which affects their duration of action in the body.
Some key points to consider when choosing between mefenamic acid and diclofenac include:
- The efficacy of diclofenac in osteoarthritis, as demonstrated in studies such as 3 and 4
- The safety profile of diclofenac, including its potential for gastrointestinal and cardiovascular adverse events, as discussed in 5
- The availability of extended-release formulations of diclofenac, which can provide longer duration of action, as noted in 2
- The pharmacokinetic properties of mefenamic acid, including its longer half-life and less frequent dosing requirements, as compared to diclofenac.
Overall, the choice between mefenamic acid and diclofenac will depend on individual patient needs and circumstances, and should be guided by the most recent and highest-quality evidence available, such as the review from 2.