Effect of Intravenous Pentoxifylline in Inflammatory Response in Patients Undergoing Nephrolithotomy

The Effect of Preoperative Pentoxifylline on Postoperative Pain and Development of Secondary Hyperalgesia in Patients Undergoing Laparoscopic Appendectomy: A Randomized, Double-Blind, Placebo-Controlled Trial Study

BACKGROUND

After surgery and loss of anesthetic effect, postoperative pain can annoy the patient and affect patient satisfaction with treatment. This study was aimed at evaluating the effect of preoperative pentoxifylline (PTX) on postoperative pain and development of secondary hyperalgesia in patients undergoing laparoscopic appendectomy (LA).

METHODS

This randomized, double-blind, placebo-controlled clinical trial study was conducted on 91 eligible subjects with acute appendicitis referred to Shahid Beheshti hospital of Sabzevar, Iran, in 2018. The intervention and control groups were administered with a single oral dose of PTX (10 mg/kg) and placebo an hour before surgery, respectively. Postoperative pain was measured within 24 hours after surgery using a VAS, and the area of secondary hyperalgesia was measured 24 hours after surgery using the Stubhaug et al. method.

RESULTS

The mean age of the subjects was 26.74 ± 9.99 years, and 57.14% were female. Pain intensity during rest was significantly greater in the control group as compared to the PTX group 24 hours after surgery (VAS scores 2.19 ± 0.49 and 3.13 ± 0.66, respectively; P < 0.001). Moreover, pain intensity during cough was substantially lower in the PTX group compared with the control group 24 hours after surgery (VAS scores 2.65 ± 1.90 and 4.10 ± 2.60, respectively; P = 0.003 in turn). The dynamic hyperalgesia was significantly greater in the control group as compared with the PTX group (3.80 ± 1.82 and 7.43 ± 2.38, respectively; P < 0.001).

CONCLUSIONS

Findings suggest that oral administration of PTX 1 hour before surgery in patients undergoing LA can reduce postoperative pain in patients and prevent secondary hyperalgesia at a surgical site.

Identification of novel analgesics through a drug repurposing strategy

The identification of new indications for approved or failed drugs is a process called drug repositioning or drug repurposing. The motivation includes overcoming the productivity gap that exists in drug development, which is a high-cost–high-risk process. Repositioning also includes rescuing drugs that have safely entered the market but have failed to demonstrate sufficient efficiency for the initial clinical indication. Considering the high prevalence of chronic pain, the lack of sufficient efficacy and the safety issues of current analgesics, repositioning seems to be an attractive approach. This review presents example of drugs that already have been repositioned and highlights new technologies that are available for the identification of additional compounds to stimulate the curiosity of readers for further exploration.

Drug repositioning: playing dirty to kill pain

The number of approved new molecular entity drugs has been decreasing as the pharmaceutical company investment in research and development is increasing. As we face this painful crisis, called an innovation gap, there is increasing awareness that development of new uses of existing drugs may be a powerful tool to help overcome this obstacle because it takes too long, costs too much and can be risky to release drugs developed de novo. Consequently, drug repositioning is emerging in different therapeutic areas, including the pain research area. Worldwide, pain is the main reason for seeking healthcare, and pain relief represents an unmet global clinical need. Therefore, development of analgesics with better efficacy, safety and cost effectiveness is of paramount importance. Despite the remarkable advancement in research on cellular and molecular mechanisms underlying pain pathophysiology over the past three decades, target-based therapeutic opportunities have not been pursued to the same extent. Phenotypic screening remains a more powerful tool for drug development than target-based screening so far. It sounds somewhat heretical, but some multi-action drugs, rather than very selective ones, have been developed intentionally. In the present review, we first critically discuss the utility of drug repositioning for analgesic drug development and then show examples of 'old' drugs that have been successfully repositioned or that are under investigation for their analgesic actions. We conclude that drug repositioning should be more strongly encouraged to help build a bridge between basic research and pain relief worldwide.