作者：Laurie Barclay, MD
出處：WebMD醫學新聞
December 12, 2008 — 美國食品藥物管理局（FDA）日前宣布，使用口服磷酸鹽製劑與急性磷腎病變有關。
根據FDA安全資訊與不良反應通報系統MedWatch的警訊，FDA因此要求處方OSPs Visicol的廠商（Salix藥廠）與OsmoPrep（Salix藥廠）在仿單上加註警示。
FDA藥物評估與研究中心的Janet Woodcock醫師在一項新聞稿中表示，雖然少見，但這項嚴重不良反應與使用口服磷酸鈉有關，不論是處方還是非處方用藥。
在某些病例中，這些嚴重的不良反應發生在過去沒有健康因素的病患身上，這可能致使他們處於發生腎臟損傷的風險中；然而，我們無法排除某些病患在使用OSP產品前就已經有脫水的現象，或是他們在使用OSP產品後並沒有喝足夠的水。
除了Visicol與OsmoPrep之外，這經常使用於清腸、或做為大腸鏡以及其他檢查準備用，OSP產品包括非處方緩瀉劑，例如Fleet Phospho-soda（C.B. Fleet公司）。
當用於清腸時，OSP產品被證實與某些沒有急性腎衰竭明顯危險因子的病患發生急性磷腎病變有關；然而，這些病患中，某些在使用OSPs之前就脫水了，或是在使用OSPs後沒有飲用足夠的水分，這些都可能增加發生急性磷腎病變的風險。
在急性磷腎病變中，磷酸鈣沉積在腎小管中，在那裡它們可能造成嚴重、永久的腎功能受損。
因為使用OSP而發生急性磷腎病變的危險因子，包括年齡大於55歲、低體容積、血管內容積不足以及腎臟功能不全、腸阻塞、或是使用該藥物前有大腸炎。使用可能降低腎臟灌流或是功能的藥物也可能增加風險。這些藥物包括利尿劑、血管張力素酵素抑制劑、血管張力素受體抑制劑，可能還包括非類固醇抗發炎藥物。
對於那些有上述任何危險因子的病患，FDA建議使用OSP產品作為清腸用途應該要小心；OSP產品禁用於18歲以下兒童，或是與其他含有磷酸鈉的緩瀉藥物併用。
為了確保使用OSP產品的好處大於發生急性磷腎病變的風險，FDA委任製造廠商提供風險評估與減輕策略，包括藥物使用說明、上市後的臨床研究來進一步評估使用OSP所造成急性腎臟損傷的風險。
因為OSP作為安全的非處方緩瀉藥物已經有很長的一段時間，FDA將會繼續讓這個藥物用於這些適應症。然而，FDA警告非處方OSP產品不應該以高於緩瀉劑量的高劑量用於清腸，並將發出一份修正來移除這些非處方使用OSP產品用於清腸的聲明。OSP產品應該僅可以在健康照護專業人員的處方下，才能使用於清腸。
任何有關OSP產品的不良反應都應該通報到FDA的MedWatch通報計畫，可以透過電話1-800-FDA-1088、傳真到1-800-FDA-0178或是線上通報到http://www.fda.gov/medwatch，或是郵件寄送到5600 Fishers Lane, Rockville, MD 20852-9787。
Oral Sodium Phosphate Products Linked to Acute Phosphate Nephropathy
By Laurie Barclay, MD
Medscape Medical News
December 12, 2008 — Acute phosphate nephropathy has been reported in association with the use of oral sodium phosphate products (OSPs), the US Food and Drug Administration (FDA) announced yesterday.
The FDA has therefore required the manufacturer of prescription OSPs Visicol (Salix Pharmaceuticals) and OsmoPrep (Salix Pharmaceuticals) to add a boxed warning to the labeling for these products, according to an alert sent yesterday from MedWatch, the FDA's safety information and adverse event reporting program.
"Though rare, these are serious adverse events associated with the use of oral sodium phosphates — both prescription and over-the-counter products," Janet Woodcock, MD, director of FDA's Center for Drug Evaluation and Research, said in a news release.
"In some cases, these serious adverse events occurred in patients with no pre-existing health factors that would have put them at risk for developing kidney injury," Dr. Woodcock said. "We cannot rule out, however, that some of these patients were dehydrated prior to ingestion of OSP products or they did not drink sufficient fluids after ingesting OSP products."
In addition to Visicol and OsmoPrep, which are used for bowel cleansing and preparation before colonoscopy or other procedures, OSPs include over-the-counter laxatives such as Fleet Phospho-soda (C. B. Fleet Company).
When used for bowel cleansing, OSPs have been linked to acute phosphate nephropathy in some patients without apparent risk factors for developing acute kidney injury. However, some of these patients may have been dehydrated before using OSPs or may have had inadequate fluid intake after use of OSPs, which would increase the risk for acute phosphate nephropathy.
In acute phosphate nephropathy, calcium-phosphate crystals deposit in the renal tubules, where they may cause serious, permanent impairment of kidney function.
Risk factors for developing acute phosphate nephropathy as an adverse event of OSP use include age greater than 55 years, hypovolemia, decreased intravascular volume, and renal impairment, bowel obstruction, or active colitis at baseline. Use of medications that may impair renal perfusion or function may also increase risk. These include diuretics, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and possibly nonsteroidal anti-inflammatory drugs.
For patients with any of the above risk factors, the FDA recommends that OSP prescription products be used with caution for bowel cleansing. OSP products are contraindicated in children younger than 18 years or in combination with other laxatives containing sodium phosphate.
To ensure that the benefits of OSPs outweigh the risks of acute phosphate nephropathy, the FDA is mandating a risk evaluation and mitigation strategy by the manufacturer, including a medication guide, as well as a postmarketing clinical trial to further evaluate the risk of acute renal injury with OSP use.
Because OSPs have a long history of safe use as over-the-counter laxatives, the FDA will continue to allow their availability in this setting. However, the FDA warns that over-the-counter laxative OSPs should not be used for bowel cleansing at a higher dose than the recommended laxative dose, and it will issue an amendment to remove the professional labeling for bowel cleansing for these OSPs available over-the-counter. OSPs should only be used for bowel cleansing when prescribed by a healthcare professional.
Adverse events related to use of OSPs should be communicated to the FDA's MedWatch reporting program by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at http://www.fda.gov/medwatch, or by mail to 5600 Fishers Lane, Rockville, MD 20852-9787.
[ 本帖最後由 goodcat1111 於 2008-12-23 10:38 編輯 ] |
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