Pseudoephedrine
Nasal decongestants
Nasal decongestants
An oral decongestant that shrinks nasal vessels; it can raise blood pressure and heart rate and must never be taken with MAO inhibitors.
Quick facts
- Group
- Nasal decongestants
- Target
- Noradrenaline release from sympathetic nerve endings (indirect), with some direct alpha action
- Used for
- Nasal congestion of colds
- Key effects
- Nervousness · Difficulty sleeping
- Monitor
- Blood pressure and heart rate · Sleep and nervousness
- ATC
- R01BA02
No doses: the clinician sets them by the current guideline.
Mechanism of action
Pseudoephedrine is a stereoisomer of ephedrine. It acts mostly indirectly: it is taken up into sympathetic nerve endings and displaces noradrenaline, which then stimulates alpha-adrenergic receptors in the nasal mucosa and constricts its swollen vessels. Because it acts throughout the body, it also raises blood pressure and heart rate, stimulates the brain (insomnia, nervousness) and tightens the bladder neck.
- Pseudoephedrine enters sympathetic nerve endings
- It releases noradrenaline onto alpha receptors
- Nasal vessels constrict and the swelling falls
- The same effect elsewhere raises blood pressure
Indications
- Nasal congestion of colds Common cold (acute viral rhinopharyngitis) →
- Nasal congestion of allergic rhinitis, usually with an antihistamine Allergic rhinitis →
- Sinus congestion and pressure Acute rhinosinusitis →
Adverse effects
Common
- Nervousness, restlessness and dizziness
- Difficulty sleeping
- Fast heartbeat and palpitations
- Raised blood pressure
Contraindications
- Taking an MAO inhibitor or within two weeks of stopping one
- Children under 4 years with non-prescription products
- Caution in hypertension, heart disease, diabetes, hyperthyroidism, glaucoma and prostate enlargement
Key interactions
- MAO inhibitors
- Hypertensive crisis
- Other sympathomimetics and stimulants
- Additive rise in blood pressure and heart rate
- Antihypertensives, including beta-blockers
- Reduces their blood-pressure-lowering effect
- Theophylline
- Additive stimulant effects
What is monitored
- Blood pressure and heart rate in patients with cardiovascular disease
- Sleep and nervousness
- Urination in older men
Administration and safety
- Oral tablets or liquid; extended-release tablets are swallowed whole
- The last dose of the day is taken several hours before bedtime
- Sale is restricted in many countries because it can be made into methamphetamine
Pregnancy and breastfeeding
Oral decongestants are generally avoided in pregnancy, especially in the first trimester; the clinician decides.
Nursing care
- Check blood pressure before use in patients with hypertension or heart disease
- Ask about MAO inhibitors and stimulants
- Teach to stop and seek advice if symptoms last more than a week or come with fever
Pharmacokinetics
- Absorption
- Well absorbed by mouth; immediate- and extended-release forms
- Metabolism
- Little metabolism
- Elimination
- Mostly unchanged in the urine; faster in acidic urine
- Onset and duration
- Within about half an hour
Test yourself
Think of the answer, then tap the question to see it.
Does pseudoephedrine act mainly directly or indirectly on adrenergic receptors?
Mainly indirectly, by releasing noradrenaline from sympathetic nerve endings.
Which drug class makes pseudoephedrine dangerous, and what happens?
MAO inhibitors; hypertensive crisis.
Why is pseudoephedrine a problem in an older man with an enlarged prostate?
Alpha stimulation tightens the bladder neck and can cause urinary retention.
Connections
← Back to the class: Nasal decongestants
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Pseudoephedrine: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); Decongestants - NHS (NHS, 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.