Rx FAQ: What are “as-needed” medications?

A young woman stops on a hike to use her rescue inhaler, which is an example of an as-needed medication.

You have a headache, so you reach for some Tylenol® or Advil®. You have heartburn, so you reach for some Tums®. Thanks to “as-needed” medications like these, relief is always at your fingertips.

As-needed medications, also known as pro re nata (PRN) medications, are typically taken to manage acute symptoms. Think pain, allergies, insomnia, digestive issues, migraines, asthma attacks or anxiety.

Unlike maintenance medications that are taken regularly to prevent symptoms or manage chronic conditions regardless of current symptoms, as-needed medications provide relief on an as-needed basis and should be stopped as soon as symptoms go away.

Because as-needed medications offer targeted relief precisely when you need them most, they are often indispensable additions to your medicine cabinet. They also give you flexibility because they aren’t taken on a strict schedule, making it easy for you to tailor your own treatment to your current needs.

Prescription PRNs

We often think of PRNs as over-the-counter medications like Advil, Tylenol, Pepcid AC® or Benadryl®. But there are many as-needed medications that require a prescription from your healthcare provider. Here are some common examples:

  • Rescue inhalers like Albuterol provide quick, immediate relief during an asthma attack.
  • Migraine medications such as Imitrex or Maxalt® are prescribed to alleviate migraine symptoms when they arise.
  • Anti-anxiety medications like Xanax® or Ativan® are sometimes prescribed for rapid relief during an acute episode of anxiety or a panic attack.
  • Nitrostat® is a medication prescribed to quickly treat an acute episode of chest pain.

There are other situations where your doctor may prescribe a medication we typically think of as “as needed” for daily use. For example, some people take Zyrtec® every day for allergy prevention.

Always make sure to read the medication label before taking any as-needed medications. And reach out to your pharmacist or doctor if you have any questions or concerns about dosage or medication interactions.

Monitor expiration dates

Unlike medications that we take daily, as-needed medications may sit unused in your medicine cabinet for extended periods of time between episodes of symptoms. This increases the likelihood of expiration. Expired medications may lose their potency or even become harmful over time.

To ensure the effectiveness and safety of your medications, make it a habit to check expiration dates routinely and dispose of any expired medications properly.

Our pharmacists are here for you

Whether you’re taking an “as-needed” over-the-counter or prescription medication, Express Scripts® Pharmacy is here to help. Our dedicated pharmacists are available 24/7 to answer all your questions and concerns to help make sure you get the fast relief you need in the safest way possible.


Posted date: May 13, 2024

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