Ropivacaine spinal anesthesia is not antagonized by ondansetron pretreatment.
BACKGROUND
We investigated a possible effect of ondansetron on the duration of sensory and motor block produced by ropivacaine.


METHODS
Fifty male patients undergoing transurethral surgery received either 8 mg oral ondansetron the evening before surgery plus IV 8 mg ondansetron 15 min before subarachnoid anesthesia or placebo. All patients received 2.2 mL of 0.75% plain ropivacaine intrathecally. Sensory and motor block were assessed 30 min after the intrathecal injection and every 30 min thereafter until recovery from the motor block.


RESULTS
Thirty minutes after spinal injection of ropivacaine, we first measured, in both groups, the time to maximum block for both sensory and motor modalities. The maximum level of the sensory block, defined as decreased sensation, was T8 in the control and T6 in the ondansetron group, and absence of sensation was defined as T11 and T9 for the control and the ondansetron groups, respectively. Regarding block duration, 180 min after spinal injection, sensory block was detected in 11 of 22 and 16 of 24 patients and motor block in 1 of 22 and 0 of 24 in the control and ondansetron groups, respectively. Sensory and motor block did not differ between groups at any measured time point.


CONCLUSIONS
Ondansetron had no effect on the subarachnoid sensory or motor block produced by ropivacaine.
Department of Anesthesiology, Aretaieio Hospital,Medical School, University of Athens, Athens, Greece.
Anteia
A
Paraskeva
Vassiliki
V
Chatziara
Ioanna
I
Siafaka
Marianna
M
Zotou
Argyro
A
Fassoulaki
D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000577:Amides / Q000008:administration & dosage*; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000932:Antiemetics / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004347:Drug Interactions; D006801:Humans; D007275:Injections, Intravenous; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D017294:Ondansetron / Q000008:administration & dosage*; D017288:Pain Threshold / Q000187:drug effects; D011229:Preanesthetic Medication; D000077212:Ropivacaine; D013997:Time Factors; D013521:Urologic Surgical Procedures, Male
D000577:Amides; D000779:Anesthetics, Local; D000932:Antiemetics; D017294:Ondansetron; D000077212:Ropivacaine