专家视点——三种最不合理的老年用药

科罗拉多州埃斯蒂斯帕克——科罗拉多大学丹佛分校的老年医学专家Jeffrey I. Wallace博士在该校主办的内科新进展研讨会上列举了三种最不合理的老年用药。

醋酸甲地孕酮(Megace)：醋酸甲地孕酮广泛用于食欲不佳和营养维持不良的老年患者，但随访6~12个月的随机试验明确显示，患者接受2~3个月治疗后在体重增加方面的受益较小。该药物属于孕激素，与血栓形成事件风险增加相关，并有可能增加死亡率。

Wallace博士强调：“有关醋酸甲地孕酮的数据看起来真的很糟。对于恰好有抑郁症状的患者，我更倾向于应用米氮平增加患者食欲。在开具醋酸甲地孕酮之前，我可能会使用药用大麻(屈大麻酚)。”

口服铁剂超过1次/d：Wallace博士指出，经常看到出院后老年患者每天服用3次铁剂。铁在十二指肠和空肠被主动吸收， 1次/d铁剂的吸收比例大约为75%， 2次/d提高至90%，而3次/d则再提高5%。因此，每日服用次数每增加1次，铁的吸收率会有所增加，但问题是胃肠道副作用也大幅增加。大多数出院患者的身体状况并不是很好，若再使他们承受便秘、消化不良和食欲下降等副作用，则得不偿失。Wallace博士自称是1次/d铁剂的坚定支持者。

Wallace博士还强调，口服铁剂良好吸收需要酸性环境，因此服用质子泵抑制剂将会影响铁的吸收。铁剂与橙汁或维生素C同服将有助于吸收，虽并非总是奏效，但不妨一试。

肌肉松弛剂：肌肉松弛剂具有镇静作用，可致抗胆碱能副作用，与跌倒风险增加相关，且其疗效也受到质疑。Wallace博士指出，过去通常对65或70岁老年背痛急诊患者开具Flexeril(环苯扎林)或其他类似药物，但目前其所在大学医院已不再这样做。肌肉松弛剂实际上并不是止痛药，辅助止痛效果不佳。对于一般背痛老年患者，他宁愿开具阿片类药物而非肌肉松弛剂。他强调，除非患者确有肌肉痉挛，否则使用止痛药物足矣。

Wallace博士报告无利益冲突。

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By: BRUCE JANCIN, Internal Medicine News Digital Network

ESTES PARK, COLO. – Topping Dr. Jeffrey I. Wallace’s pantheon of peeves in prescribing for the elderly are:

• Megestrol acetate (Megace): These are widely prescribed in older patients who aren’t eating well and are experiencing failure to thrive. But the randomized trials with 6- to 12-month followup clearly show that any modest benefit achieved in terms of weight gain takes 2-3 months of therapy. And megestrol acetate is a progestational agent associated with increased risk of thrombotic events and a possible increase in mortality.

"The data on Megace really look terrible. I much prefer using mirtazapine to increase appetite in a patient with even a hint of depression. I’d probably use medical marijuana in the form of Marinol [dronabinol] before I’d use Megace," declared Dr. Wallace at an update in internal medicine sponsored by the University of Colorado, Denver, where he is a professor of medicine.

• Oral iron more than once daily: "I see patients in the nursing homes all the time who’ve been discharged from the hospital by the surgeons on T.I.D. (three times a day) iron," according to the geriatrician.

Absorption of iron is an active process occurring in the duodenum and jejunum. By taking once-daily iron, a patient gets roughly 75% of all the iron that can possibly be absorbed in a day. Moving up to B.I.D. iron, that figure rises to 90%, and T.I.D. dosing bumps up another 5%.

"So each time, I get a little more iron absorbed. The problem is I get a lot more GI side effects. Most of the geriatric patients I see after they get out of the hospital aren’t feeling good already – and now I’m going to make them constipated and give them some dyspepsia and decreased appetite? It’s just not worth it; you don’t get much more bang for the buck. I’m pretty much a stickler to always take the iron down to once a day," he said.

A tip: Oral iron requires an acid environment to be absorbed well. A patient who has had a GI bleed or is at increased risk because of chronic NSAID therapy is likely to be on a proton pump inhibitor, which will interfere with iron absorption. "Have the patient take the iron with some orange juice or vitamin C to help absorption. The data isn’t all that good that it makes much difference, but it’s worth a try," according to the geriatrician.

• Muscle relaxants: These medications are sedating; cause anticholinergic side effects and are linked to an increased risk of falls; and are of questionable efficacy.

"It used to be that if you were 65 or 70 [years old] and came to the ED with back pain, everyone walked out of there with Flexeril [cyclobenzaprine] or some variant thereof. Our ED at the university pretty much doesn’t hand out muscle relaxants anymore. They’re not really pain pills; the data are terrible in terms of helping pain. For run-of-the-mill back pain, I’d rather give an older patient an opiate than a muscle relaxant. So unless you have a definitive muscle spasm, treat the pain with pain pills," he urged at the conference.

He reported having no financial conflicts.