1. Why are expiration dates important for consumers to pay attention to?

Drug expiration dates reflect the time period during which the product is known to remain stable, which means it retains its strength, quality, and purity when it is stored according to its labeled storage conditions.

2. How are expiration dates established?

FDA regulations require drug applicants to provide stability testing data with a proposed expiration date and storage conditions when they submit an application for FDA approval of their drug.  This testing is designed to provide confidence that the product will meet the applicable standards of strength, quality, and purity throughout its shelf-life. The FDA verifies that an applicant’s proposed expiration date is supported by appropriate studies that the applicant has conducted.

For non-application drugs, such as over-the-counter monograph products, the manufacturer must also conduct stability testing to establish an expiration date and storage conditions to meet FDA’s regulations (see 21 CFR 211.166 as well as related sections 211.137 and 211.160) . 

FDA recommends that applicants and manufacturers follow the recommendations in internationally harmonized guidance documents on stability testing such as the International Council on Harmonization guidance documents (ICH) Q1(A-F) and Q5C.

FDA inspections of manufacturing facilities may include an evaluation of the firm’s stability testing program to verify that labeled expiration dates are supported by a scientifically sound study and appropriate data.

3. Can expiration dates be extended?

FDA’s guidance for industry, “Changes to an Approved NDA or ANDA” explains that the manufacturer of an approved drug product may extend the expiration date for the drug product based on their own testing and acceptable data in accordance with a protocol approved in the new drug application (NDA) or abbreviated new drug application (ANDA) (see 21 CFR 314.70).  To help alleviate drug shortages, FDA has also approved extensions of expiration dates when data supporting the extension are available.

4. What potential risks are associated with expired drugs?

It’s important to be aware that there are several potential harms that may occur from taking an expired medicine or one that may have degraded because it was not stored according to the labeled conditions. If a drug has degraded, it might not provide the patient with the intended benefit because it has a lower strength than intended. In addition, when a drug degrades it may yield toxic compounds that could cause consumers to experience unintended side effects. Patients with serious and life-threatening diseases may be particularly vulnerable to potential risks from drugs that have not been stored properly.  There are a number of simple steps consumers can take to dispose of expired medications.

5.  Does FDA conduct testing to extend expiration dates?

FDA supports a public health program involving other partners to extend the expiration dates for a limited number of carefully selected drug products. Under the Shelf-Life Extension Program (SLEP), FDA conducts testing for certain products stored in federal stockpiles in environmentally controlled locations.  (Federal stockpiles are stores of certain drugs that might be needed to prevent or treat diseases or conditions which may occur during a public health emergency.)  SLEP is a fee-for-service program through which the labeled shelf life of certain federally stockpiled products can be extended after select products undergo periodic stability testing conducted by FDA.

Drugs held by consumers may have been stored under varied conditions after entering the market.  As a result, it would be difficult to conduct testing to determine expiration dates that would be meaningful and generally applicable after prolonged periods of storage under different conditions. The appropriate conditions will depend on the drug, but may include considerations regarding temperature, humidity, and exposure to light.

1.为什么有效期期对患者来说很重要?

药品有效期反映了已知产品保持稳定的时间，这意味着它在根据其标签的储存条件储存时可以保持其强度、质量和纯度。

2.如何确定有效期？

FDA法规要求药品申请人在提交FDA批准其药品的申请时提供稳定性测试数据，包括建议的有效期和储存条件。该测试旨在为产品在整个有效期内满足强度、质量和纯度的适用标准提供信心。FDA确认申请人提出的有效期是否得到申请人所进行的适当研究的支持。

对于非应用药品，例如非处方各论产品，生产商也必须进行稳定性测试，以确定有效期和储存条件，以满足FDA的规定(见21 CFR 211.166以及相关章节211.137和211.160)。

FDA建议申请人和生产商遵循国际统一的稳定性测试指导文件中的建议，例如国际协调指导文件(ICH) Q1(A-F)和Q5C。

FDA对生产设施的检查可能包括对公司稳定性测试程序的评估，以确认所标注的有效期是由科学合理的研究和适当的数据支持的。

3.有效期可以延长吗？

FDA的行业指南“已批准NDA或ANDA的变更”有解释，已批准药品的生产商可以根据自己的测试和可接受的数据，根据新药申请(NDA)或简化新药申请(ANDA)中批准的协议延长药品的有效期(见21 CFR 314.70)。为了帮助缓解药品短缺，当有数据支持延长有效期时，FDA也批准延长有效期。

4.过期药品有哪些潜在风险？

重要的是要意识到，服用过期药品或由于没有按照标签条件储存而可能降解的药品，可能会产生几种潜在的危害。如果药品已经降解，它可能无法为患者提供预期的益处，因为它的强度低于预期。此外，当药品降解时，可能会产生有毒化合物，导致患者产生意想不到的副作用。患有严重和危及生命疾病的患者可能特别*受到未妥善储存药品的潜在风险的影响。患者可以采取一些简单的步骤来处理过期的药品。（官网附着这些具体的simple steps ）

5.FDA是否进行测试以延长有效期？

FDA支持与其他合作伙伴一起的公共卫生项目，以延长精心挑选的有限数量药品的有效期。根据有效期延长计划(SLEP)， FDA对储存在环境受控的联邦储备库中的某些药品进行测试(联邦储备库存储了预防或**突发公共卫生事件期间可能发生的疾病或状况所需的某些药品)。SLEP是一项收费服务计划，通过该计划，在选定的药品经过FDA进行的定期稳定性测试后，某些联邦储备药品的标签有效期可以延长。

患者持有的药品在进入市场后可能已经在不同的条件下储存。因此，很难进行测试，以确定在不同条件下长期储存后有意义且普遍适用的有效期。适当的条件将取决于药品，但可能包括考虑温度、湿度和光暴露。