These outcomes concluded that there was a reduction in urgency to urinate, a decrease in micturitions and a decrease in average volume voided per micturition. There is also an improvement observed of the symptoms when Vibegron is administered over a longer period (52 weeks) concluding that it is effective and safe for longer use. In severe patients, increasing the dose was accompanied by similar beneficial effects when there was first a lack of these. Quality of life of the patients is improved, including a reduction of nocturia. Adverse effects
The most common side effects of Vibegron are a dry mouth, constipation, headache, nasopharyngitis, diarrhea, nausea, bronchitis, urinary tract infection and upper respiratory tract infection. An indication is made that upon urinary retention development, the patient should stop using the drug. Risk assessment for the drug in pregnant women has yet to be evaluated. Interactions
Vibegron is in contrast to other OAB drugs very selective and leads to a lesser degree in unwanted side effects. Vibegron is found to be a substrate for CYP3A4 in vivo, but does not actually induce or inhibit any of the cytochrome P450 enzymes and is thus less likely to take part in drug–drug interactions (DDI). Here vibegron differs from the previous overactive bladder drug mirabegron, which was known to be associated in various drug–drug interactions by inhibiting CYP2D6 or inducing CYP3A4, CYP2D6 and CYP2C9 in the liver.Using Vibegron only (monotherapy) has positive effects on OAB and UUI, but a combination with other drugs can have additional effects.
The drug has a bioavailability of 90%, and peak plasma concentrations are seen after 2–4 hours. The mean drug half-life is approximately 11 hours. Mexiletine is predominantly metabolised by the liver. The pharmacokinetics of mexiletine are preserved with even moderate to severe renal impairment, but dose adjustment may be required when creatinine clearance falls below 10 mL/minute. Synthesis
Society and culture
Mexiletine is available for human use in the US, and has been reintroduced in the UK as a licensed product, having previously only been available as a named patient import. The drug is sold under the trade name Mexitil for use in arrhythmias and NaMuscla for use in myotonia. Veterinary uses
Mexiletine is available to veterinarians in the US for the treatment of heart disease in dogs and cats. It is commonly used for the treatment of arrhythmogenic right ventricular cardiomyopathy (ARVC) in Boxer dogs in combination with sotalol. References
Further reading
Peck T, Hill S, Williams M, eds. (2004). Pharmacology for Anaesthesia and Intensive Care (2nd ed.). Cambridge University Press. ISBN 0-521-68794-2. External links
"Mexiletine". Drug Information Portal. U.S. National Library of Medicine.