If you currently prescribe bethanechol chloride for urinary retention, please raise your hand

✍ Scribed by Jerry G. Blaivas

• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 87 KB
• Volume: 3
• Category: Article
• ISSN: 0733-2467
• DOI: 10.1002/nau.1930030402

✦ Synopsis

As a medical student I was taught to treat postoperative urinary retention, in otherwise healthy patients, with a single subcutaneous dose of 2.5 mg bethanechol. Sometimes it worked, sometimes it did not. During internship, women who could not void after minor gynecologic procedures were treated with S.C. bethanechol. Sometimes it worked, sometimes it did not. As general surgeons, we treated young men who could not void after herniorrophy with S.C. bethanechol. Sometimes it worked, sometimes it did not. As an academic urologist I studied the effects of S.C. bethanechol on various cystometric parameters. It seemed to work! But what did it do? It produced a severe urge to void at lower bladder volumes than those of controls. It raised the initial pressure in the bladder and the pressure during filling. It decreased bladder capacity. But it also increased maximal urethral closure pressure. It did not increase flow rate, nor did it decrease residual urine. In global terms, it seemed to increase the desire to void by shifting the cystometric curve up and to the left. But does it make people void who could not void before? Does it make the bladder contract when it could not contract before? I think not. Except sometimes.

It is these "sometimes" that compound the issue. Most of us in academic urology seem to agree that bethanechol is ineffective, except that "sometimes" it seems to work. In the current issue of this journal and in his previous work on this subject, John Downie has done much to clarify the problem. A number of points should be emphasized. Most important, in order to be effective in promoting micturition, there must be an intact sacral micturition reflex arc. Thus, bethanechol's use in patients with complete lower motor neuron lesions and in spinal shock is doomed to failure. Second, at least in acute situations, bethanechol is ineffective when administered orally (and the muscarinic side effects of the subcutaneous route usually preclude its clinical use). Third, there have been no reasonable clinical trials of bethanechol in those patients in whom the drug is most likely to be clinically effective, ie, those with incomplete lower motor neuron lesions.

I personally do not believe that bethanechol, in its current form, is a very useful drug. It may work in some neurologically normal patients by malung them so uncomfortable (by shifting the cystometrogeum curve to the left) that they void because it is too uncomfortable not to void. It does not make much sense to me to administer a drug that exerts an effect all of the time in order to accompiish an event 01984 Alan R. Lk, Inc.