Generic Name

Pseudoephedrine

Mechanism

• Peripheral adrenergic agonist: acts primarily as an indirect sympathomimetic—stimulating α‑1 adrenergic receptors on vascular smooth muscle.
• Norepinephrine release: promotes vasoconstriction in the nasal mucosa, decreasing vascular permeability and edema.
• Selectivity: minimal β‑adrenergic activity at therapeutic doses, thus limited respiratory bronchodilation effects.

> *Result*: sharp reduction in nasal congestion, rapid onset (~30 min), duration ≈4–6 h.

Pharmacokinetics

• Absorption: nearly complete oral bioavailability (~50‑70 % after standard tablets).
• Peak plasma concentrations (Tmax): 1–2 h post‑dose.
• Half‑life: 3 – 4 h (shorter in older patients, longer with renal impairment).
• Metabolism: minor N‑demethylation to methamphetamine (in vitro) – no clinically significant activity in humans.
• Elimination: primarily renal (≈90 % unchanged), requiring dose adjustment in severe renal disease.
• Special considerations: crosses the placenta (category C); minimal breast‑milk excretion.

Indications

• Upper‑respiratory congestion from:
• Common cold, sinusitis
• Allergic rhinitis
• Acute rhinosinusitis
• Adjunct in combined decongestant–antihistamine formulations.
• Non‑prescription use: oral tablets (30–60 mg), extended‑release formulations, and nasal sprays (≤0.4 % concentration).

Contraindications

• Absolute:
• Sympathetic crisis (pheochromocytoma)
• Recent MAO‑I use (last 14 days)
• Relative:
• Hypertension (needs monitoring)
• Ischemic heart disease, arrhythmias
• Glaucoma, benign prostatic hyperplasia (BPH)
• Pregnancy (category C) and lactation (avoid)
• Drug interactions:
• MAO‑Is, serotonergic agents (risk serotonin syndrome)
• Anticholinergic drugs (additive effects)
• CYP2D6 substrates/alters metabolism? (limited evidence)

Dosing

| 5 days increases risk of rebound congestion.

> *Tip*: Use the lowest effective dose for the shortest duration.

Adverse Effects

• Common: insomnia, nervousness, tachycardia, hypertension, dry mouth, headache, dizziness.
• Serious:
• Hypertensive crisis (especially in susceptible patients)
• Arrhythmias & ischemic events
• Vision changes (glaucoma)
• Psychosis or agitation (rare at high doses)
• Abuse potential: raw material for methamphetamine synthesis → strict regulatory control and limits on OTC purchases (e.g., bottle‑size restrictions).

Monitoring

• Vital signs: BP & HR at baseline and during therapy in at‑risk patients.
• Renal function: CrCl in patients >65 y or with CKD.
• Symptom control: No daily use >5 days → reassess.
• Pregnancy/lactation: discourage use; offer alternatives.

Clinical Pearls

1. Don’t stack: avoid combining with other sympathomimetics (e.g., phenylephrine) to reduce hypertensive risk.

2. Use with caution in patients on SSRIs/other serotonergic meds—watch for serotonin syndrome signs.

3. High‑risk subgroups: screen hypertensive patients; consider a 24‑h BP log during treatment.

4. Alternative in CYA: If a child <6 y requires symptomatic relief, opt for a monotherapy antihistamine rather than a decongestant.

5. Regulatory control learning point: Many regions restrict OTC sales to 120 mg per 30 mL bottle; a pharmacy check is nowadays mandatory.

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• *This card integrates key drug facts, safety considerations, and practical tips for both learners and clinicians.*