Pseudoephedrine (Sudafed)
Sympathomimetic amine used as an oral nasal decongestant. Acts via mixed direct (alpha and beta adrenergic receptor agonism) and indirect (norepinephrine release from sympathetic nerve terminals) mechanisms to produce vasoconstriction in nasal mucosa. Behind-the-counter (BTC) status in many countries due to its role as a methamphetamine precursor. Primarily renally excreted unchanged (55-75%) with a half-life of 5-8 h. Carries important interaction warnings: hypertension risk (especially in hypertensive patients or with high doses) and ABSOLUTELY CONTRAINDICATED with MAOIs due to risk of severe hypertensive crisis from potentiated catecholamine effect.
Projected serum levels — 60 mg, once daily
Maintenance schedule: 60 mg once daily (oral).
Modeled steady state after ~1 days: peak ≈ 48.1 mg, trough ≈ 4.2 mg body load. Population-based estimate over 15 days for a 60 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Decongestant
- Route modeled
- Oral
- Model confidence
- inferred
- Half-life
- 6 h
- Common dose
- 60 mg
- Suggested maximum
- 240 mg/day
- Reference dose range
- 30–240 mg (single dose)
- Suggested cadence
- once daily
- Validated against
- 60 mg oral — Cmax 0.18 mg/L at 2 h
Documented interactions
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danger
Apigenin + Pseudoephedrine (Sudafed)
Apigenin reversible_inhibitor of CYP1A2 predicted to change Pseudoephedrine (Sudafed) AUC by ~3.33x
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danger
Ciprofloxacin (Cipro) + Pseudoephedrine (Sudafed)
Ciprofloxacin (Cipro) reversible_inhibitor of CYP1A2 predicted to change Pseudoephedrine (Sudafed) AUC by ~3.33x
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danger
DIM (Diindolylmethane) + Pseudoephedrine (Sudafed)
DIM (Diindolylmethane) inducer of CYP1A2 predicted to change Pseudoephedrine (Sudafed) AUC by ~0.50x
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danger
Epinephrine (Adrenalin) + Pseudoephedrine (Sudafed)
Epinephrine (Adrenalin) and Pseudoephedrine (Sudafed) both push the alpha1 adrenergic, alpha2 adrenergic, and beta2 adrenergic in the same direction.
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danger
Ethinyl Estradiol + Pseudoephedrine (Sudafed)
Ethinyl Estradiol reversible_inhibitor of CYP1A2 predicted to change Pseudoephedrine (Sudafed) AUC by ~3.33x
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danger
Fluvoxamine (Luvox) + Pseudoephedrine (Sudafed)
Fluvoxamine (Luvox) reversible_inhibitor of CYP1A2 predicted to change Pseudoephedrine (Sudafed) AUC by ~3.33x
Serum checks 40 modeled interaction pairings for pseudoephedrine (sudafed) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.
Research behind this entry
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Efficacy and safety of single and multiple doses of pseudoephedrine in the treatment of nasal congestion associated with common cold
Placebo-controlled RCT demonstrating pseudoephedrine 60 mg significantly reduced nasal airway resistance and congestion scores in common cold, with rapid onset (30 min) and sustained effect over 4-6 hours, validating…
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Substitution of phenylephrine for pseudoephedrine as a nasal decongestant: an illogical way to control methamphetamine abuse
Influential editorial documenting that oral phenylephrine (the behind-the-counter replacement for pseudoephedrine in many jurisdictions) has negligible oral bioavailability due to extensive gut wall and first-pass…
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Pharmacokinetics of oral decongestants
Comprehensive PK review of pseudoephedrine, phenylephrine, and phenylpropanolamine, establishing pseudoephedrine's superior oral bioavailability (~95%) versus phenylephrine (~38%), renal elimination dependency on…
3 published studies referenced in the app, each with a plain-language summary.