Parenteral tetracycline (TET) and doxycycline (DOX) are cost-effective and safe in producing pleurodesis but mostly unavailable currently. We investigated whether oral forms of TET/DOX can produce pleurodesis as does parenteral DOX.
Parenteral DOX (10 mg/kg), or filtered oral TET (35 mg/kg)/DOX (10 mg/kg) was injected intrapleurally in 2 cc saline through a chest tube in 3-kg rabbits. When daily aspirated pleural fluid volume was below 5 cc/24 hour, the chest tube was removed. The fluid volumes, and white blood cell (WBC), lactate dehydrogenase (LDH) and protein levels on the 1st day after the injection were recorded. After sacrificing on the 14th day, pleurodesis was graded from 1 (none) to 8 (complete symphysis) by two observers blinded to treatment groups.
Oral TET (capsule/tablet-n:6) and DOX (capsule/tablet-n:7) were as effective as parenteral DOX (n:10) in producing pleurodesis [right pleurodesis scores: TET capsule- 7.50 (6.00), tablet- 6.50 (6.00); DOX capsule- 4.00 (1.00), tablet- 8.00 (5.00); parenteral DOX- 7.50 (6.00); p=0.235]. The left scores were 1.00 in all 36 rabbits. A positive correlation existed between right scores and fluid total volume (r=0.523, p=0.001) or protein level (r=0.577, p=0.0004). Fluid total volume, WBC, LDH and protein levels were comparable excluding WBC in TET tablet versus DOX parenteral groups (p=0.047). Only fluid 24-hour volume and WBC level differed (p<0.05) between oral (n:26) and parenteral groups (n:10), and only 72-hour volume between TET and DOX capsule groups in four oral groups. The complications were non-fatal [right hemothorax- TET capsule (3) / tablet (2); DOX tablet (2); parenteral DOX (2); left hemothorax- TET capsule (1); ascites- parenteral DOX (1)]. There was no growth on culture of filtered oral specimens. TET/DOX capsule/tablet costed less than parenteral DOX (<$1 versus $4.72/rabbit). Filtering oral forms increased the cost by $1.12/rabbit.
Oral TET/DOX is more cost-effective than and as safe as parenteral DOX in producing pleurodesis in rabbits.
Oral TET/DOX can be used for pleurodesis in humans when parenteral forms of these drugs are not available.
S. Bilaceroglu, None.