Analgesic efficacy of acetaminophen sustained release

Area of Science:

• Pharmacology
• Pain Management
• Drug Delivery Systems

Background:

• Post-surgical pain, particularly after oral surgery, requires effective and sustained analgesic management.
• Acetaminophen is a widely used analgesic, but its immediate-release formulations may have limitations in duration of action for moderate to severe pain.

Purpose of the Study:

• To compare the analgesic efficacy of acetaminophen sustained release (SR) and immediate-release plus sustained-release (IR + SR) formulations against standard acetaminophen tablets.
• To evaluate the impact of different dosages and release profiles on pain intensity, duration, and overall pain relief.

Main Methods:

• A double-blind, randomized study involving 200 outpatients experiencing pain after lower third molar extraction.
• Administration of various acetaminophen formulations: SR (1000 mg, 2000 mg), IR + SR (250 + 750 mg, 500 + 1500 mg), and standard tablets (500 mg, 1000 mg).
• Pain intensity was assessed hourly using a visual analog scale over 12 hours, with efficacy measured by peak effect, pain reduction, duration of effect, and pain reduction index.

Main Results:

• Acetaminophen SR 2000 mg achieved a 54% pain reduction, compared to 37% for the 500-mg standard tablet.
• The peak effect for SR 2000 mg was 67% after 2.6 hours, an improvement over the 500-mg tablet's 53% at 1.9 hours.
• The sustained-release formulation significantly enhanced the duration of analgesic effect without diminishing the peak pain relief.

Conclusions:

• Acetaminophen sustained-release formulations offer improved and longer-lasting analgesia for post-oral surgery pain compared to immediate-release standard tablets.
• The SR formulation demonstrates a favorable balance of sustained pain relief and peak efficacy, suggesting potential for enhanced patient recovery.