Study design and randomization This study is a randomized controlled trial. Randomization
will be performed using software and a block randomization scheme. Study assignment will be
completed using sequentially numbered sealed opaque envelopes. All the research procedures
described other than the use or not of phenazopyridine will be applicable to both arms of the
study. Subjects will have a 50% chances of getting either phenazopyridine or nothing.
Because pyridium turns the urine orange, it is impossible to blind the patients and
researchers to the study assignment. Because there is no known placebo that turns the urine
orange, there is no value to using an actual placebo tablet. Subjects will be assigned to
either receive pyridium or not receive pyridium preoperatively.
Screening potential subjects: Investigators will screen potential subjects for
contraindications to methylene blue. Prior obtaining the routine surgical consent for the
potential subject's surgical procedure, the patient's medical history in the UMass Electronic
Medical Record is routinely reviewed. The medical record will be reviewed for a diagnosis of
G6PD and if found, the potential subject will be excluded.
Once written consent has been obtained, subject number will be assigned and the appropriate
randomization envelope will be opened. The study assignment will not be formally shared with
the subject. Those assigned to the "pyridium" arm will have orders written for the standard
200 mg dose of pyridium to be given on arrival to the Surgical Admissions Care Unit (SACU).
Those assigned to the "NO pyridium" arm with have their routine preoperative orders written
along with an order for "No preoperative pyridium".
Subjects will then follow the routine perioperative care for their procedures with the only
study interventions being the gathering of PHI and performing postoperative pain assessments.
PHI will be obtained at the time of the surgical consent with the purpose to evaluate for
possible confounders affecting the postoperative bladder function.
Surgical procedure:
The Mid Urethral Sling will be performed in standard fashion based on manufacturer's
recommendations and instructions to minimize inter-observer variations. We will perform the
procedure according to our usual and customary techniques. The subject will receive the same
technique and interventions that a routine patient on the Urogyn service would expect to
undergo. There will be no changes to the technique for the purpose of the study.
Bladder challenge:
Patient will undergo voiding trial at same day surgery per our usual and customary protocol.
This is the same protocol the subject would undergo as a patient on the Urogyn service. The
bladder challenge will be interpreted in our usual manner and the subject managed according
to our routine clinical protocols.
Postoperative care:
Subjects will undergo routine postoperative care and followup. Subjects failing their bladder
challenge will be seen in the Urogyn clinic according to routine clinical protocols and data
concerning their void trials collected. Subjects will undergo routine followup evaluation 6
weeks postoperatively in the order to assess any potential long-term voiding dysfunction.
Information on any postoperative complications will be collected
Administration of Visual analog scale:
(1) Visual analog scale for assessment of pain will be administered at two- time intervals.
VAS #1) Preoperative VAS will be done by the principal investigator or any of the study
assistants. The VAS form will be part of subject's packet.
VAS#2) VAS will be administered by one of the study investigators 2 to 3 hours after the
surgical procedure in the SACU.