颅内高压患者服用乙酰唑胺可改善视力

4月22日刊登在《美国医学会杂志》（JAMA）上的一篇研究称：特发性颅内高压伴轻度视力减退的患者低钠减肥饮食联合口服乙酰唑胺改善视野功能的效果优于单纯饮食低钠减肥饮食。

爱荷华大学医院与医学中心的迈克尔·沃尔博士及其研究团队完成了此项研究。研究人员随机分配165例特发性颅内高压伴轻度视力减退患者口服乙酰唑胺或安慰剂。乙酰唑胺用法为每日两次、剂量逐渐增加至视神经乳头水肿级别低于1（Frisén 量表）或双眼的周围平均差（PMD）均提高至少–1dB，最大剂量不超过每次4g。乙酰唑胺组和对照组同时进行饮食和生活习惯的调整。

乙酰唑胺组和对照组的基准PMD均为–3.53dB，6个月后，前者升至–2.10dB，后者升至–2.82dB，乙酰唑胺组较高（治疗差异0.71 dB）。此外，乙酰唑胺组的视神经乳头水肿改善情况（Frisén 量表；治疗差异–0.70）和视力相关生存质量（视功能问卷；治疗差异6.35）均优于对照组。研究人员称治疗组的体重较单纯锻炼组减轻了4.05kg，但乙酰唑胺对PMD的改善并非源自体重的改变。

乙酰唑胺组感觉异常、味觉障碍、乏力、胃肠道反应、耳鸣等不良反应的发生率显著高于对照组。但研究人员称：“据我们所知，研究中没有患者因服用乙酰唑胺发生不可逆损害。”

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By: AMY KARON, Cardiology News Digital Network

FROM JAMA

VITALS

Major finding: After 6 months of treatment, the acetazolamide group had an average perimetric mean deviation of –2.10 dB, compared with –2.82 dB for the placebo group.

Data source: A 6-month, double-blind multicenter trial of 165 patients with idiopathic intracranial hypertension and mild vision loss who followed a low-sodium weight loss diet and were randomized to either daily oral acetazolamide or placebo.

Disclosures: The National Eye Institute funded the study. Two coauthors reported receiving personal fees from Teva Pharmaceutical Industries, which produces generic acetazolamide.

In patients with idiopathic intracranial hypertension and mild vision loss, adding oral acetazolamide to a low-sodium weight loss diet improved visual field function more than diet alone, researchers reported. The study was published online April 22 in JAMA.

Perimetric mean deviation (PMD) – the primary outcome measure – differed by less than 1 dB between the two groups, reported Dr. Michael Wall of the University of Iowa Hospitals and Clinics in Iowa City and his associates with the Neuro-Ophthalmology Research Disease Investigator Consortium (NORDIC). The clinical relevance of the difference "remains to be determined," the investigators said.

The researchers randomized 165 patients with idiopathic intracranial hypertension and mild vision loss (PMD, –2 to –7 dB) to oral acetazolamide or placebo. Patients received up to 4 g acetazolamide twice daily. Initial doses were increased until papilledema grade fell below 1 on the Frisén scale and PMD improved to at least –1 dB in both eyes. Both groups also followed a diet and lifestyle modification program, according to the investigators (JAMA 2014;311:1641-51[doi:10.1001/jama.2014.3312]).

Baseline PMD was –3.53 dB in both groups. At 6 months, PMD averaged –2.10 dB in the acetazolamide group and –2.82 dB in the placebo group (treatment difference, 0.71 dB; 95% CI, 0- 1.43 dB; P = .050).

The acetazolamide group also had greater mean improvements in papilledema grade (treatment effect, –0.70; 95% CI, –0.99 to –0.41; P less than .001) and vision-related quality of life on the VFQ-25 (Visual Functioning Questionnaire–25) survey tool (treatment effect, 6.35; 95% CI, 2.22-10.47; P = .003). And the treatment group lost 4.05 kg more weight than the exercise-only group (95% CI, –6.27 to –1.83 kg; Pless than .001), the researchers said. A statistical mediation analysis showed that most of the effect of acetazolamide on PMD was not due to weight loss, they reported.

However, the functional importance of specific decibel improvements in PMD are poorly understood, Dr. Wall and his associates noted. "Our chosen minimal clinically important difference for PMD was 1.3 dB and was based on a small pilot study designed to estimate the level of decibels at which a clinician makes a decision to change therapy," they said. "Our estimated treatment effect was only approximately half of this value."

The acetazolamide group was significantly more likely to develop paresthesia, dysgeusia, fatigue, decreased carbon dioxide level, nausea, vomiting, diarrhea, and tinnitus than the exercise-only group, the investigators reported. "No participant, to our knowledge, experienced permanent morbidity from receiving acetazolamide," they added.

The National Eye Institute funded the study. Two coauthors reported receiving personal fees from Teva Pharmaceutical Industries, which produces generic acetazolamide.