Iodopovidone is as effective as doxycycline in producing pleurodesis in rabbits

Abstract

Background and objective:The mechanism by which iodopovidone achieves pleurodesis is unknown. This study investigated whether iodopovidone is as effective as doxycycline in producing pleurodesis and whether systemic corticosteroids diminish its efficacy. Methods: Four groups of seven New Zealand rabbits were assigned to the following intrapleural treatment groups: 2 mL of 2% iodopovidone, 2 mL of 4% iodopovidone, 2 mL of 4% iodopovidone plus 0.8 mg/kg triamcinolone intramuscularly weekly and 10 mL/kg doxycycline in 2 mL. Pleural fluid was collected 24, 48 and 72 h after intrapleural injections and analysed for WCC, protein and LDH levels. The rabbits were killed 2 weeks after the injections. Pleurodesis was graded macroscopically on a scale from 1 to 8. The degree of microscopic pleural fibrosis and pleural inflammation was graded from the HE stain slides. Results: The mean volume of pleural fluid as well as the mean total WCC was significantly lower in the steroid-treated group than in the other groups. The degree of the resulting pleurodesis was similar in the 2% iodopovidone (7.00 Ϯ 1.29), 4% iodopovidone (7.71 Ϯ 0.76) and doxycycline (7.14 Ϯ 0.90) groups (P > 0.05) whereas the pleurodesis score of the steroid group (3.71 Ϯ 1.98) was significantly lower than all other groups (P < 0.05). The degree of microscopic pleural fibrosis and pleural inflammation was significantly lower in the steroid group than in the 2% iodopovidone or 4% iodopovidone group. Conclusions: Both 2% and 4% iodopovidone can induce pleurodesis as efficaciously as doxycycline in rabbits. Systemic corticosteroids significantly decrease the efficacy of iodopovidone in producing pleurodesis.Key words: doxycycline, iodopovidone, mechanism, pleurodesis, steroid. INTRODUCTIONPleurodesis is frequently considered for the management of recurrent pneumothoraces or pleural effusions. Pleurodesis is produced by the intrapleural injection of a sclerosing agent that induces an inflammatory response and a subsequent fibrotic process that leads to fusion of the parietal and visceral pleura, obliterating the pleural space. 1,2 Currently, the three primary agents used for pleurodesis are talc, bleomycin and tetracycline (TCN) derivatives. However, none of these sclerosing agents is ideal. TCN has been considered the agent of choice for pleurodesis in patients with symptomatic malignant pleural effusions and recurrent pneumothoraces. 3 The i.v. form of TCN used for pleurodesis is no longer available and the intrapleural injection of all TCN derivatives sometimes produces severe pain. In addition, the parenteral forms of doxycycline and minocycline are not available in many counties. Bleomycin is relatively expensive (around US$1000/ patient) and is probably less efficacious than the TCN derivatives or talc. 4 Talc preparations are not SUMMARY AT A GLANCEThis study used a rabbit model to compare the effectiveness of iodopovidone in causing pleurodesis with that of doxycycline and investigated the mechanism by which iodopovine acts. Iodopovidone produ...

Iodopovidone pleurodesis in the treatment of refractory pleural effusions

“…It is also necessary for it to have a high molecular weight along with chemical polarity, low regional clearance, rapid systemic clearance, and a steep dose-response curve. [6,9] Along with commonly used agents like talc, tetracycline, and doxycycline iodopovidone should be accepted as an alternative sclerosing agent [1] as it is an inexpensive and readily available agent for chemical pleurodesis. [10] Previous studies have suggested that the use of iodopovidone has a high success rate.…”

“…[1][2][3] Several agents have been described and used for chemical pleurodesis, and they have a success rate ranging from 60-94%. [4] Talc, tetracycline, and doxycycline are the most popular and widely used sclerosing agents, but none of these have solved the problem definitively.…”

“…[5] Iodopovidone has been used for pleurodesis to treat refractory pleural effusions and has been shown to be safe and effective in several studies, whether it was administered at the time of the thoracoscopy or applied through a chest tube. [1,6] This study was conducted to evaluate the efficacy of iodopovidone pleurodesis in 43 patients with refractory pleural effusions.…”

New agents for pleurodesis

“…There has been one study on rabbits evaluating the efficacy of iodopovidone [15]. Guo and associates [15] administered 2 mL 2 % or 4 % iodopovidone intrapleurally to rabbits and reported that pleurodesis was equivalent to that produced by 10 mg kg −1 doxycycline.…”

“…Guo and associates [15] administered 2 mL 2 % or 4 % iodopovidone intrapleurally to rabbits and reported that pleurodesis was equivalent to that produced by 10 mg kg −1 doxycycline. If 0.8 mg kg −1 triamcinolone was administered weekly intramuscularly to the rabbits that received iodopovidone, the extent of pleurodesis was markedly reduced [15]. It seems that iodopovidone is an effective agent for producing pleurodesis.…”