Transdermal diclofenac patch was found to be as effective as oral diclofenac but it was more safe than and oral diclofenac for management of post endodontic pain.

Post endodontic pain presents a significant challenge for endodontists, as it is annoying for patients. Patients experiencing dental pain and dealing with poorly managed dental pain defer treatment. The treatment of post-endodontic pain is the field of endless research demonstrating the need for better modalities and effective formulations which may replace the existing management options for significant improvement in pain and quality of life.

Non-steroidal anti-inflammatory drugs (NSAIDs) has been the drug of choice for treatment of dental pain due to their significant efficacy by inhibition of cyclo-oxygenases 1 and 2 (COX-1 and COX-2). Oral administration of NSAIDs may lead to loss of some drug before its systemic absorption in the first-pass metabolism. This may lead to cause gastrointestinal discomfort and side effects, being dependent on the dose of the drug.

To nullify the various adverse events associated with the oral use of NSAIDs, several other alternatives for drug administration are devised. Administration of drug in the general blood circulation through the skin has been used as a viable alternative to the oral or parenteral route. It reduces the gastrointestinal adverse events that frequently occur with the oral administration of the drug, as it avoids the first-pass metabolism and is steadily absorbed over hours or days. Topical mode of administration is another effective alternative to oral administration which may act as a remedial analgesic modality with a low incidence of adverse events and purported benefits.

Transdermal drug delivery has also proven useful in pain management by achieving target delivery, consistent absorption over hours and reducing the frequency of dose. A special membrane is employed in trans membrane patch for controlled drug flow through the skin to the bloodstream. The undisturbed permeation of drug through skin allows for achieving consistent drug levels, which is considered as the main objective of drug therapy. Diclofenac is one such effective NSAID, which is administered through both oral and transdermal route to reduce pain and inflammation. It is routinely utilised for the control of dental pain following various dental treatments.

Rationale behind research

Previous studies lack in establishing the efficacy of diclofenac for achieving post-endodontic analgesia. Also, no direct comparisons have been made in establishing the efficacy of both oral and transdermal use of diclofenac in dental patients. Therefore, this study was conducted. 

Objective

The present study was conducted to compare the efficacy and safety of transdermal diclofenac patch and oral diclofenac for management of post-endodontic pain.

• Study outcomes

The study outcomes included evaluation of the intensity of pain using Visual Analogue Scale (VAS), the number of rescue medication tablets taken and adverse events. 

• Time Points:  4, 8, 12 and 24 h postoperatively 

Outcomes

Baseline: There were no significant differences observed at baseline

Study outcomes:

• A substantial reduction was observed in the postoperative VAS scores in both study groups, with a gradual decrease from day 1-2 in both groups.
• None of the patients in both study groups required paracetamol as rescue analgesia.
• The incidence of adverse events was greater in the patients receiving oral diclofenac (Group II) compared to patients receiving transdermal diclofenac patch. (Fig.2)

In the present study diclofenac has been administered in two different forms: transdermal (100mg) and oral (50mg). The transdermal patch of 5 cm2 patch bestowed the sustained release of the active agent, diclofenac diethylamine. Diclofenac is lipophilic as an organic acid, but its salts are soluble in water at neutral pH. These properties aid in easy penetration of the drug through cell membranes, including the skin and synovial lining of diarthrodial joints. Previous studies conducted by Cordero et al. reported the excellent transdermal penetration properties of diclofenac.

A gradual decrease in pain intensity scores was observed from day 1 to day 2 with both oral and transdermal routes of administration of diclofenac, on the evaluation of pain intensity after endodontic therapy of premolars. These findings were similar to the results of the study conducted by the Dhanapal et al. who had assessed the effectiveness of a single dose of transdermal diclofenac patch compared to three oral doses per day for the management of endodontic pain.

The safety and tolerability analysis of the drug in its oral and transdermal formulation demonstrated the incidence of gastrointestinal discomfort and other adverse events in 12 out of 16 patients administered with oral diclofenac; however, no patients in the transdermal diclofenac group reported any adverse events. A previous study performed by Agarwal et al. determined localised erythematous rash at the site of the application when the transdermal patch of diclofenac was used for the attenuation of venous cannulation.

The findings of the present study were favourable as each successive application of the drug was done at a different site of the body. The tolerability and safety of transdermal patch have been suggested by results studies reporting the analgesic efficacy of transdermal diclofenac patch in sports injuries and osteoarthritis, and findings of a systematic review conducted by Mason et al. which revealed the efficacy of topical NSAIDs.