藥物警訊

Noxafil (posaconazole): Drug Safety Communication - Dosing Errors when Switching between Different Oral Formulations; Label Changes Approved

AUDIENCE: Internal Medicine, Infectious Disease

ISSUE: The FDA is cautioning that differences in dosing regimens between the two oral formulations of the antifungal Noxafil (posaconazole) have resulted in dosing errors. To help prevent additional medication errors, the drug labels were revised to indicate that the two oral formulations cannot be directly substituted for each other but require a change in dose. Direct mg for mg substitution of the two formulations can result in drug levels that are lower or higher than needed to effectively treat certain fungal infections.

Since the approval of Noxafil delayed-release tablets in November 2013, FDA received eleven reports of the wrong oral formulations being prescribed and/or dispensed to patients. One case resulted in death, and an additional case resulted in hospitalization. According to the reports, these outcomes were a result of health care professionals not knowing that the two oral formulations cannot be substituted for each other without adjusting the dose due to differences in how the medicine is absorbed and handled by the body.

In addition to changes to the outer carton of Noxafil (see Photos in Drug Safety Communication), its manufacturer Merck revised the prescribing information and the patient information in the drug label to alert patients and their health care professionals that the two oral formulations of Noxafil cannot be substituted for each other.

BACKGROUND: Noxafil is approved in two oral formulations: an oral suspension and a delayed-release tablet. It is also approved as an intravenous solution for injection. Noxafil is used to help prevent certain invasive fungal infections caused by fungi called Aspergillus and Candida. Noxafil is used in patients who have an increased chance of getting these infections due to weakened immune systems. Noxafil oral suspension is also used to treat a fungal infection called thrush caused by Candida in the mouth or throat area.

RECOMMENDATION: Prescribers should specify the dosage form, strength, and frequency on all prescriptions they write for Noxafil. Pharmacists should request clarification from prescribers when the dosage form, strength, or frequency is not specified. Patients should talk to their health care professional before they switch from one oral formulation to the other.

Read the MedWatch safety alert, including links to the Drug Safety Communication, at http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHuma...

美國FDA發布藥物安全警訊，提醒抗黴菌感染製劑Noxafil (posaconazole)兩種不同的口服劑型（口服懸液劑及緩釋錠劑）其給藥劑量範圍不同，不可直接轉換使用。為了避免此錯誤發生，美國FDA將於藥品仿單加註警語。若兩種不同口服劑型直接以相同mg給藥，可能會導致藥品濃度過高或過低，而影響黴菌感染的治療。

Noxafil具有兩種口服劑型：口服懸液劑及緩釋錠劑，也備有靜脈注射製劑。可用於預防由Aspergillus和Candida兩種黴菌菌種造成的感染。Noxafil常用於因免疫力低下可能增加感染機會的病人，而口服懸液劑也用於因Candida引起之口腔或喉部鵝口瘡。

Noxafil緩釋錠於2013年11月核准上市後，美國FDA陸續接獲11起因開方或調劑錯誤的口服劑型造成之給藥錯誤案例。其中一例導致死亡，一例則需住院治療。經分析這些案例，主要原因為醫療人員不清楚此兩種口服劑型於體內吸收方式不同，不可在未經劑量轉換之下直接取代使用。

藥品廠商除了於Noxafil外包裝加註不可直接轉換之資訊外，同時也更新藥品仿單之處方資訊及病人用藥資訊，以提醒病人及醫療人員此兩種口服劑型不可直接取代使用。美國FDA也提醒開方者於開立Noxafil時應明確指示使用之劑型、劑量或頻率，若有不清楚的部分，藥師於覆核時也應向處方者確認以上資訊。病人若需轉換不同的口服劑型，應先向醫療人員確認後再使用。

相關訊息與連結請參考FDA網址：

http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHuma...

[Posted 01/07/2016]

資料來源：美國FDA之藥物安全警訊

資料提供：台大醫院藥劑部