What Are ‘PRN’ Medications, and When Are They Given?

In the world of medicine, there are many different terms and acronyms that can be confusing for people seeking treatment. One such term is “PRN medication.” PRN is an acronym for the Latin phrase “pro re nata.” In English, it means “as needed.”

As its acronym suggests, these medications are prescribed to be taken as needed, rather than on a regular schedule. They’re commonly used to treat symptoms that pop up every now and then — such as pain or insomnia.

Being able to take medications as you see fit can be liberating — but certain situations may require a little more guidance than others. Below, we’ll answer some common questions about PRN medications and when you should take them.

What are ‘as needed’ medications?

PRN (as needed) medications have a flexible dosing frequency. You only take them when you need them. This means you have the freedom to choose if and when you take them. You don’t need to use them routinely.

For example, you may take a PRN medication to relieve a mild headache after a night out. Unless you experience chronic headaches or migraines, you probably don't take headache medication every day. Taking headache medication every day in a scheduled manner would be a routine use, not an as needed use.

How are PRN medications different from other drugs?

The main difference between PRN medications and other drugs is that PRN medications are taken based on how you’re feeling at the moment. They’re not typically needed consistently or over long stretches of time.

PRN medications may also provide faster relief of symptoms than other medications, and they often remain in the body for a shorter amount of time. For instance, rescue inhalers like albuterol (Ventolin) promptly address asthma symptoms, such as difficulty breathing and shortness of breath. These quick-acting inhalers provide breathing control during an asthma attack, but they’re not meant to be used on a daily basis.

By comparison, you can think of medications you fill routinely at the pharmacy as “maintenance medications.” These are generally taken every day regardless of your symptoms. This is because they may take a longer time to become effective, or daily use is necessary for consistent symptom control. Maintenance asthma inhalers, such as fluticasone/salmeterol (Advair), help control breathing symptoms over time.

Many other maintenance medications are also available. Statin medications, like atorvastatin (Lipitor), are taken daily to reduce high cholesterol and may take several weeks to fully kick in. Blood pressure medications, like lisinopril (Zestril), also work best when taken every day.

Examples of PRN medications

Many PRN medications are available for use. You can find some over the counter (OTC) and others with a prescription from your healthcare provider. Some examples include:

• Pain and fever reducers, like ibuprofen (Advil, Motrin) and acetaminophen (Tylenol)

• Allergy medications, like diphenhydramine (Benadryl) and cetirizine (Zyrtec)

• Heartburn medications, like calcium carbonate (Tums) and famotidine (Pepcid AC, Zantac 360)

• Rescue inhalers, like albuterol

• Opioid medications, like oxycodone (OxyContin) and hydrocodone/acetaminophen

• Benzodiazepine medications, like alprazolam (Xanax) and clonazepam (Klonopin)

• Triptan migraine medications, like sumatriptan (Imitrex) and rizatriptan (Maxalt)

• Medications used for chest pain relief, specifically nitroglycerin (Nitrostat)

Keep in mind: This is not an exhaustive list. And there may be situations where your healthcare provider recommends taking certain PRN medications every day, depending on what you’re treating. For instance, some people take antihistamines, like Zyrtec, every day — not as needed — for allergy prevention. If you’re curious if a medication you take is meant to be taken daily or as needed, ask your pharmacist.

When are PRN medications given?

Since many PRN medications are available OTC, you can decide when to pick them up from your local pharmacy. You might also keep certain medications stocked at your house for when symptoms arise. Common examples are ibuprofen andacetaminophen. Depending on your situation, you may take the recommended dose every 4 to 6 hours as needed to relieve pain or fever.

Other OTC medications, likeBenadryl, are also taken as needed for allergy symptoms.You may also see diphenhydramine used in combination with ibuprofen, acetaminophen, or dextromethorphan (Delsym, Robitussin) in various cold and flu products. These are also used as needed.

Certain prescription medications also fall under the PRN umbrella — but this depends on what you’re treating as well as other factors. For instance, opioid medications, likeoxycodone, are often taken as needed for pain. They’re usually saved for people experiencing moderate tosevere pain symptoms, such as pain after a surgery. However, some people take opioids every day for chronic pain. 

Many prescription anxiety medications, such as benzodiazepines, are also prescribed as PRN medications.

What are the benefits and risks of PRN medications?

PRN medications give you the opportunity to self-manage your symptoms. Symptoms of a health condition can vary for everyone, so being able to choose when a medication is necessary can feel empowering. Self-managing symptoms can also prevent medication overuse if you feel like a medication is not actually needed.

What’s more, PRN medications can help strengthen the relationship you have with your healthcare provider. PRN medications can guide communication about the symptoms you’re experiencing and allow you to work in a partnership with your provider to improve your health.

However, there are some downsides. Confusing directions and a lack of guidance for when PRN medications should be used are two common complaints from those seeking treatment. When medication directions are unclear, this can lead to accidental misuse and worsen the risk for medication-related side effects.

If you’re unsure about how or when to take your medication, be sure to ask your healthcare provider or pharmacist for help.

Can PRN medications be addictive?

Yes, depending on the medication. Alongside their benefits, some PRN medications — such as opioids and benzodiazepines — carry a risk for physical and mental dependency.

Opioids and benzodiazepines are controlled substances. Controlled substances like these have a higher potential for dependency and misuse than medications that aren’t controlled. In some cases, their use can lead to situations such as substance use disorder.

It’s important to have a conversation with your healthcare provider to clarify how and when to take these types of medications. Keep in mind that even if you’re taking these medications exactly as directed, they still carry a risk for dependence.

If you or someone you know struggles with substance use, know that help is available. Call SAMHSA’s National Helpline at 1-800-662-4357 to learn about resources available in your area.

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Written by:

Wiktoria Jedrzejczyk, PharmD Candidate

Wiktoria has worked in community pharmacy since 2017 as a pharmacy technician and pharmacy intern for Wegmans Food Markets. While interning at Wegmans, Wiktoria led a project focused on building stronger relationships with patients through education about the Shingrix vaccine — which prevents shingles.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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