Short answer: Pseudoephedrine (Sudafed) is a decongestant sold without a prescription but kept behind the pharmacy counter. It is not a controlled substance, but because it can be used to make methamphetamine, federal law limits how much you can buy and requires ID. It can raise blood pressure and heart rate.
Key takeaways
- What it is: Pseudoephedrine is a decongestant (sympathomimetic) and not a federally controlled substance.
- Main uses: Nasal congestion.
- Timing: effects start in about 30 minutes and last 4 to 6 hours (12 to 24 hours ER).
- Most dangerous mix: MAO inhibitors (within 14 days), which can cause hypertensive crisis.
- Naloxone: it does not reverse this drug, but give it whenever opioids could be involved.
- Dependence risk: Low.
- Legal route: sold without a prescription; follow the Drug Facts label.
What is pseudoephedrine?
Pseudoephedrine shrinks swollen blood vessels in the nose and sinuses, relieving congestion from colds, allergies, and sinus infections.
The oral decongestant phenylephrine, sold on regular shelves, does not work by mouth. An FDA panel concluded this in 2023, and in 2024 the FDA proposed removing oral phenylephrine from the market, leaving pseudoephedrine as the effective oral option.
Quick facts
| Fact | Pseudoephedrine |
|---|---|
| Generic name | Pseudoephedrine hydrochloride or sulfate |
| Brand names | Sudafed; in Claritin-D, Allegra-D, Zyrtec-D, Advil Cold and Sinus |
| Drug class | Sympathomimetic decongestant |
| US legal status | Over the counter behind the counter; List I chemical |
| Purchase limits | 3.6 g a day and 9 g in 30 days, with photo ID and a logbook |
| Forms | Tablets, extended-release tablets, liquid |
| Onset | About 30 minutes |
| Half-life | About 5 to 8 hours |
How long does pseudoephedrine last?
- Starts working: About 30 minutes
- Effects last: 4 to 6 hours (12 to 24 hours ER)
- Half-life: About 5 to 8 hours
Timing varies with the dose, the form, how it is taken, liver and kidney function, age, and other drugs taken at the same time.
What are the biggest risks of pseudoephedrine?
Common side effects include restlessness, insomnia, fast heartbeat, and nervousness.
Blood pressure and heart: it can raise blood pressure; people with uncontrolled high blood pressure or heart disease should ask a clinician first.
Rare brain effects: European regulators reviewed rare cases of posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome in 2023 and added warnings.
What should you never mix with pseudoephedrine?
| Combined with | What happens | Guidance |
|---|---|---|
| MAO inhibitors (within 14 days) | Hypertensive crisis | Contraindicated |
| Other stimulants and decongestants | Overstimulation, high blood pressure | Avoid doubling |
| Blood pressure medicines | Reduced effect | Ask a pharmacist |
| Caffeine | More jitteriness and insomnia | Limit |
Check any combination with the DoseUses combination checker or ask a pharmacist.
What are the signs of a pseudoephedrine overdose, and what should you do?
Overdose causes agitation, tremor, very high blood pressure, fast or irregular heartbeat, hallucinations, and seizures.
If someone may be overdosing
- Call 911 for chest pain, a seizure, trouble breathing, signs of a stroke (face drooping, weakness on one side, slurred speech), a very high body temperature, or if the person collapses.
- Move them somewhere cool and calm, loosen tight clothing, and cool the skin with water. Do not try to hold them down.
- If they become unresponsive or their breathing slows, give naloxone. Street stimulants are often contaminated with fentanyl.
- For advice when the person is awake and stable, call Poison Help at 1-800-222-1222.
Is pseudoephedrine addictive?
Pseudoephedrine has low misuse potential at label doses and does not cause significant withdrawal. Its main regulation is to stop it being diverted to make methamphetamine.
- After stoppingNo withdrawalCongestion may return.
- Rebound congestionNot typicalUnlike nasal decongestant sprays, oral pseudoephedrine does not usually cause rebound.
- Ongoing congestionSee a clinicianNasal steroid sprays treat allergic congestion.
See the withdrawal timelines and the full pseudoephedrine withdrawal guide.
Is pseudoephedrine legal?
Pseudoephedrine is sold without a prescription, but under the Combat Methamphetamine Epidemic Act of 2005 it must be kept behind the counter or in a locked case.
- ID and logbook: buyers must show photo ID and sign a logbook, usually electronic and shared across pharmacies.
- Limits: no more than 3.6 grams of pseudoephedrine a day and 9 grams in 30 days, regardless of the number of stores.
- State rules: some states set lower limits; Oregon required a prescription from 2006 until 2022.
Outside the United States
| Country | Status |
|---|---|
| United Kingdom | Pharmacy medicine with pack-size limits |
| Australia | Pharmacist-only medicine with real-time sales recording |
| Mexico | Banned since 2008 |
| International | Listed precursor chemical (Table I of the 1988 UN Convention) |
Frequently asked questions about pseudoephedrine
Why is Sudafed behind the counter?
Because pseudoephedrine can be used to make methamphetamine, federal law requires ID, a logbook, and purchase limits.
Is Sudafed PE the same as Sudafed?
No. Sudafed PE contains phenylephrine, which does not work as a decongestant when taken by mouth.
Can pseudoephedrine raise blood pressure?
Yes. People with high blood pressure should check with a clinician first.
How much pseudoephedrine can I buy?
Up to 3.6 grams a day and 9 grams every 30 days under federal law.
Can pseudoephedrine keep you awake?
Yes. Insomnia is common, so avoid late doses.
Sources
- Sudafed (pseudoephedrine) prescription information, DailyMed, US National Library of Medicine.
- FDA proposes ending use of oral phenylephrine as OTC monograph nasal decongestant active ingredient after extensive review, US Food and Drug Administration, November 2024.
- 21 CFR Part 1314, Retail sale of scheduled listed chemical products, Electronic Code of Federal Regulations.
- BeSafeRx: Your Source for Online Pharmacy Information, US Food and Drug Administration.
- International drug control conventions, United Nations Office on Drugs and Crime.
This guide summarizes the sourced DoseUses Pseudoephedrine profile, written from FDA labels, DEA rules, and federal health agencies. It is educational and is not medical advice. Last updated October 5, 2026.
