Myrbetriq获准用于治疗膀胱过度活动症

圣路易斯(医学参考)——2012年6月28日，安斯泰来制药宣布，美国食品药品管理局(FDA)已批准Myrbetriq(米拉贝隆)缓释片治疗伴急迫性尿失禁、尿急、尿频症状的膀胱过度活动症(OAB)。Myrbetriq是一种β3肾上腺素受体激动剂，每日服药1次。使用这种药物可使逼尿肌平滑肌松弛在膀胱充盈-排尿周期的存储期变得松弛，从而促进增加膀胱容量。

Myrbetriq的推荐起始剂量为25 mg，1次/d，可与食物同服也可在非进食时服用。Myrbetriq 25 mg通常会在开始治疗后8周内起效。根据个体的疗效和耐受性，剂量可增加至50 mg，1次/d。

研究者在一个以白人女性为主、平均年龄59岁的人群中对Myrbetriq进行了评估。受试者中52%此前曾使用抗毒蕈碱药物治疗OAB。Myrbetriq获得批准是基于3项安慰剂对照3期研究的安全性和有效性数据，在这些研究中，Myrbetriq 25 mg和50 mg可显著改善尿失禁和减少每24 h排尿次数。

在研究受试者中最常报告的不良反应包括高血压、鼻咽炎、泌尿系统感染和头痛。

使用Myrbetriq可增加血压。建议定期检测血压，特别是对于高血压患者。不建议对严重失控的高血压患者使用Myrbetriq。

上市后已有膀胱出口梗阻(BOO)患者和服用抗毒蕈碱药物者接受Myrbetriq治疗期间发生尿潴留的报告。对于临床显著性BOO患者应慎用Myrbetriq，对于正在服用抗毒蕈碱药物的OAB患者使用Myrbetriq也应谨慎。

Myrbetriq是一种温和的CYP2D6抑制剂，如果将Myrbetriq与美托洛尔、地昔帕明合用，CYP2D6的系统性暴露量会增加。因此，合理监测和调整剂量可能是必要的，尤其是在合用经CYP2D6代谢且治疗指数范围窄的药物时(如硫利达嗪、氟卡尼和普罗帕酮)。

爱思唯尔  版权所有

ST LOUIS (MD Consult) - On June 28, 2012, Astellas Pharma announced that the US Food and Drug Administration has approved Myrbetriq (mirabegron) extended-release tablets for the treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency. Myrbetriq is a once daily beta-3 adrenergic agonist. Use of the drug leads to relaxation of the detrusor smooth muscle during the storage phase of the urinary bladder fill-void cycle, which promotes an increase in bladder capacity.

The recommended starting dose for Myrbetriq is 25 mg once daily with or without food. Myrbetriq 25 mg is usually effective within 8 weeks of therapy initiation. On the basis of individual efficacy and tolerability, the dose may be increased to 50 mg once daily.

Myrbetriq was studied in a population of primarily white women with a mean age of 59 years. The population included both patients who had not received prior antimuscarinic pharmacotherapy for OAB (48%) and patients who had received prior antimuscarinic pharmacotherapy for OAB (52%). The approval of Myrbetriq was granted on the basis of safety and efficacy data from 3 placebo-controlled phase 3 studies, in which treatment with Myrbetriq at doses of 25 mg and 50 mg resulted in statistically significant improvement in efficacy parameters of incontinence episodes and number of urinations per 24 hours.

The most commonly reported adverse reactions in study patients were hypertension, nasopharyngitis, urinary tract infection, and headache.

The use of Myrbetriq can increase blood pressure. Periodic blood pressure determinations are recommended, especially in patients with hypertension. Myrbetriq is not recommended for use in patients with severe uncontrolled hypertension.

Urinary retention in patients with bladder outlet obstruction (BOO) and in patients taking antimuscarinic medications for the treatment of OAB has been reported in postmarketing experience in patients taking mirabegron. Myrbetriq should be administered with caution to patients with clinically significant BOO. It should also be administered with caution to patients taking antimuscarinic medications for the treatment of OAB.

Myrbetriq is a moderate CYP2D6 inhibitor and the systemic exposure to CYP2D6 substrates such as metoprolol and desipramine is increased when coadministered with Myrbetriq. Therefore, appropriate monitoring and dose adjustment may be necessary, especially with the use of drugs with a narrow therapeutic index that are metabolized by CYP2D6 (eg, thioridazine, flecainide, and propafenone).