Hi, my boyfriend was prescribed Myrbetriq and has been taking it for a few days now and we had a concern as to why the medicine is causing an increase in girth of the penis and he becomes erect with no influence at all and is not able to ejaculate. It takes about an hour after sex to deflate or as long as 4 hours if no sex is involved. The internet has not provided more information about the effects of the medicine. It s getting frustrating.
Hi, Thanks for writing in. Myrbetriq (mirabegron) reduces muscle spasms of the bladder and urinary tract. Myrbetriq is used to treat overactive bladder with symptoms of frequent or urgent urination and urinary incontinence. Your boyfriend must be experiencing Arianism which is a potential serious condition. It is to be discussed if this is an effect of the medication that he is taking for an overactive urinary bladder or is an underlying condition in him. Please discuss with his doctor regarding sustained erection and if it is related to taking of the medication, this is termed Arianism.