OnabotA safe in patients taking anticoagulants

October 16, 2019

As the number of patients who receive onabotulinumtoxinA (onabotA [Botox]) injections for overactive bladder increases, so does the age of this population and their associated comorbidities. This raises the question: Is the use of onabotA in patients who are taking anticoagulant or antiplatelet medication safe?

Chicago-As the number of patients who receive onabotulinumtoxinA (onabotA [Botox]) injections for overactive bladder increases, so does the age of this population and their associated comorbidities. This raises the question: Is the use of onabotA in patients who are taking anticoagulant or antiplatelet medication safe?

Researchers at St. George’s Hospital in London found continuation of these therapies appears to be safe in patients receiving intravesical onabotA injection for treatment of idiopathic (IDO) and neurogenic detrusor overactivity (NDO).

“Botox itself has been found to be safe in other muscle groups. All patients experience some bleeding after Botox injections, but only one complication was reported in this study, and the patient was released after an overnight stay,” said Andrew Brown, MBBS, a second-year core surgical trainee at St. George’s Hospital, who presented the results at the AUA annual meeting in Chicago. He worked on the study with Jai Seth, MBBS, and colleagues.

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In the past, there has been little evidence regarding the safety of onabotA injections in patients who are taking anticoagulant or antiplatelet medication. When patients stop taking these drugs prior to treatment, they may be predisposed to thromboembolic or ischemic events. The authors sought to examine the number of significant bleeding events that occur after intravesical onabotA injection in patients who continue taking these medications.

The team conducted a retrospective study of all patients receiving onabotA injections for IDO and NDO in three hospitals over a 2-year period (from January 2016 through July 2018) while taking therapeutic anticoagulant or antiplatelet medication. Patient demographic data, indication for treatment, and instances of bleeding requiring intervention all were recorded.

The authors identified 532 patients who received intravesical onabotA injections, 63 of whom (33 men and 30 women) were taking anticoagulant or antiplatelet medication at the time of the procedure. Forty-six of these patients were diagnosed with IDO, and 17 were diagnosed with NDO.

Next: One case of post-injection hematuriaOne case of post-injection hematuria

In total, the 63 patients taking anticoagulant or antiplatelet medication at the time of injection underwent 114 rounds of onabotA, with each patient undergoing one to seven rounds of treatment. The modal onabotA dose was 200 U, with dosage ranging from 100 U to 300 U.

Anticoagulant and antiplatelet use among the 63 patients included: aspirin (44), clopidogrel (37), warfarin (19), and novel/non-vitamin K oral anticoagulant (14).

Patients on warfarin who had point of care testing all had an international normalized ratio (INR) measuring less than 3.0, considered an acceptable range.

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During 114 rounds of treatment, delivered with a 3-mm needle, just one round resulted in post-injection hematuria. This incident required overnight catheterization in a hospital setting and was quickly resolved. This patient was taking rivaroxaban and received 300 U of onabotA injections through 20 sites. The patient previously had undergone radiotherapy of the prostate as well as self-catheterization.

Overall, the study indicates “relative safety” in the use of intravesical onabotA injections for patients who are continuing therapy with anticoagulant and antiplatelet therapy, including warfarin, Dr. Brown said. Given that these medical therapies have traditionally been considered a contraindication for onabotA treatment, the results may open the door for onabotA injection in this class of patients.