How Long Does Sudafed Stay in Your System? Plus, 7 More Sudafed FAQs

When you have a stuffy nose and go to the pharmacy looking for relief, you encounter a variety of decongestants designed to help you breathe freely again. One of them is Sudafed (pseudoephedrine), a popular decongestant that’s available behind the pharmacy counter.

Sudafed provides short-term relief from nasal and sinus congestion related to illness or allergies. It does this by squeezing and narrowing blood vessels in your nose and sinuses.

Generally, Sudafed comes in two main forms: immediate-release (IR) and extended-release (ER) tablets. The ER versions offer longer-lasting relief, which means less frequent doses, but they take longer to kick in. An oral liquid is also available.

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With multiple product options available, knowing when to choose or avoid a certain one is important. Here are eight insider tips about how long Sudafed stays in your system and what else to keep in mind on your next decongestant-related trip to the pharmacy.

1. How long does Sudafed stay in your system?

In general, it takes some time for the body to fully excrete, or get rid of, medication. So, even after Sudafed’s decongestant effects wear off, the medication lingers in your body for a little while. 

Sudafed usually exits the body within 1 to 4 days, depending on the product. The amount of time it takes can also be affected by how acidic your urine is (urinary pH). Sudafed leaves your body faster when your urine is more acidic and slower when it’s more basic (alkaline). Certain foods, medications, and illness can alter your urinary pH.

2. How long does Sudafed last?

A dose of Sudafed typically lasts 4 to 24 hours, depending on the product you take. 

You’ll likely notice nasal symptom relief for about 4 to 6 hours if you take an IR tablet and 12 hours if you reach for a standard ER version. But Sudafed Sinus Congestion 24 Hour, which contains twice as much pseudoephedrine as regular ER products, lasts for up to 1 day.

3. How long does it take Sudafed to work?

When you have a stuffy nose, you want relief immediately. So how long does it take for Sudafed to kick in? The answer is: It depends.

For IR versions of Sudafed, the effects of the medication can usually be felt within 30 minutes. But the ER versions take a little longer. An ER product will likely start working after about 1 hour.

4. What’s the best time to take Sudafed?

One of the most common Sudafed side effects is insomnia, or difficulty sleeping. In fact, over 30% of people who take Sudafed report experiencing insomnia. Because of this, it is recommended to avoid taking it after 6PM, or within several hours of bedtime. 

Thoughtful sleep hygiene habits can also be helpful in managing this side effect. Limiting caffeine intake, avoiding daytime napping, and minimizing screen time before bed are all strategies that can improve your sleep.

Speaking of caffeine, it can actually worsen the side effects of Sudafed. The combination may lead to heightened blood pressure or a faster heart rate. So it’s best to avoid taking Sudafed at the same time as consuming caffeinated foods or drinks.

5. How long can you take Sudafed?

Sudafed should only be taken as needed. It’s not meant for long-term use, and it’s important that you follow the recommended dosages on the product’s label.

Oral decongestants, like Sudafed, work by squeezing blood vessels in your sinuses. But they also affect blood vessels in other areas of your body, including those surrounding the heart. Tighter blood vessels can raise your blood pressure and heart rate. And it’s possible to see these side effects with just a few doses of a decongestant. So it’s best to limit how much you take these medications as much as possible, especially if you have a health condition like heart disease or diabetes.

In general, it’s recommended that oral decongestants should be taken for no more than 7 days in a row. If you still need relief from nasal congestion after that, or if you develop a fever at any point, it’s best to contact your healthcare provider for next steps.

6. Is pseudoephedrine the same thing as phenylephrine?

No, Sudafed is not the same as phenylephrine (Sudafed PE). It’s a different nasal decongestant. Sudafed is considered to be more effective than Sudafed PE because the body absorbs it better, but it’s riskier.

You can also find both medications in several combination products, such as Allegra-D (fexofenadine / pseudoephedrine) and DayQuil Cold and Flu (acetaminophen / dextromethorphan / phenylephrine). These combination products carry similar risks as products that only contain pseudoephedrine or phenylephrine.

7. Is Sudafed better than nasal decongestant sprays?

Sudafed isn’t necessarily a better option than a nasal decongestant spray when you’re congested. Nasal decongestant sprays, like Afrin (oxymetazoline) and Neo-Synephrine (phenylephrine), can also be found at your local pharmacy. These sprays often work within 2 to 10 minutes and typically have fewer side effects than oral decongestants.

Nasal decongestants carry their own risks, though. These products shouldn’t be used for more than 3 days at a time. If you use one longer, you can develop rebound congestion. This is when your nose becomes dependent on the nasal spray and your congestion comes back or worsens.

Good to know: Decongestant sprays should not be taken in combination with Sudafed or another oral decongestant. Taking multiple decongestants at the same time can be dangerous and cause additional side effects.

8. Is Sudafed safe to take?

For many people, Sudafed is a safe and effective decongestant when taken for a short period of time. But a few situations warrant some caution.

You should avoid Sudafed altogether if you’re allergic to any component in the product. You should also avoid it if you’ve taken a monoamine oxidase inhibitor medication, like selegiline (Zelapar, Emsam), within the past 2 weeks.

Sudafed can also be risky for people with certain medical conditions. Talk to a healthcare provider before trying a decongestant like Sudafed if you have:

• Diabetes

• High blood pressure or another heart condition

• Glaucoma

• An enlarged prostate leading to difficulty urinating

• Thyroid issues

It’s also important to note that products containing pseudoephedrine are restricted medications because they have a potential for misuse. That’s why you won’t see them in pharmacy aisles. Instead, you have to purchase pseudoephedrine-containing products at the pharmacy counter with valid identification.

In general, it's best to be mindful while taking Sudafed. Carefully follow the directions on the product’s label and contact your healthcare provider if you have any questions.

Sudafed during pregnancy

Research surrounding the safety of taking Sudafed while pregnant is mixed. For instance, in some small studies, taking Sudafed during pregnancy has been found to be associated with higher birth defects. But those results are not consistent across all studies.

The American College of Obstetricians and Gynecologists (ACOG) recommends avoiding Sudafed and other pseudoephedrine-containing products during the first 3 months of pregnancy. But it’s best to consult your healthcare provider before taking Sudafed if you’re pregnant — no matter the trimester.

Sudafed for kids

When it comes to kids, Sudafed should be used with caution. In general, the oral liquid shouldn’t be given to children under 4 years old, and the IR tablets shouldn’t be given to kids younger than 6. The ER products should not be given to children younger than 12.

For kids, Sudafed dosages are based on age. But they typically range from 15 mg to 30 mg every 4 to 6 hours, as needed.

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Written by:

Cassandra Pardini, PharmD, MS

Cassandra Pardini has been a freelance medical writer for 7 years. In that time, she has concentrated on publishing articles on medication-related information for healthcare professionals and patients.

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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