Gabapentin reduces postoperative discomfort in bladder cancer
MedWire News: Pretreatment with gabapentin reduces postoperative catheter-related discomfort (CRBD) in patients undergoing transurethral surgery for bladder cancer, study results show.
The incidence of CRBD was reduced in a dose-dependent manner in response to gabapentin and any discomfort reported was less severe in the treatment than control group.
"CRBD, defined as an urge to void or discomfort in the suprapubic region, is extremely distressing to patients with an indwelling urinary catheter in the postoperative period, left in situ for bladder drainage," say Neerja Bharti (Postgraduate Institute of Medical Education & Research, Chandigarh, India) and colleagues in Urology.
The symptoms are attributed to involuntary contractions of the detrusor smooth muscles of urinary bladder, and the drugs that suppress these contractions are the mainstay of treatment.
The antimuscarinic drugs tolterodine and oxybutynin have been tested for the prevention of CRBD with variable success; however, dry mouth is a troublesome side effect.
In the current study, the researchers assessed the efficacy of gabapentin, a structural analog of aminobutyric acid that is widely used for its anticonvulsant and antinociceptive properties.
One hundred adult patients undergoing elective transurethral resection of bladder tumor under spinal anesthesia were randomly split into three groups. Group I patients received placebo, group II patients received gabapentin 600 mg, and group III patients received gabapentin 1200 mg 1 hour before surgery.
Lumbar subarachnoid block was administered with 2.5 mL 0.5% hyperbaric bupivacaine.
Bharti et al report that the incidence of CRBD was 90% in group I, 66% in group II, and 26% in group III. The incidence of bladder discomfort was significantly lower in group III at all time points compared with group I, and at 4, 6, 12, and 24 hours compared with group II.
The severity of CRBD was also less in group II and III patients compared with group I. Fifteen patients in group I developed moderate discomfort, versus one patient in group II and none in group III. None of the patients receiving gabapentin had severe discomfort.
One patient in group II and two patients in group III complained of dizziness in the postoperative period.
"Gabapentin probably controls detrusor muscle overactivity by modulating the afferent input from the bladder and the excitability of the sacral reflex center," Bharti et al comment, adding: "The central action reduces the sensitization of dorsal horn neurons, thereby reducing the pain after inflammation and surgery."
By Andrew Czyzewski