Introduction
Sudafed is a brand name medication containing pseudoephedrine hydrochloride, a sympathomimetic amine that functions as a nasal decongestant. It is commonly used for temporary relief of nasal congestion due to the common cold, hay fever, or other upper respiratory allergies. Pseudoephedrine is available in both prescription and over-the-counter formulations, though its sale is often restricted behind pharmacy counters due to its potential use in illicit methamphetamine production.
Mechanism of Action
Pseudoephedrine exerts its therapeutic effects through direct stimulation of alpha-adrenergic receptors in the respiratory tract mucosa. This stimulation causes vasoconstriction of dilated arterioles, reducing blood flow to nasal mucosa and resulting in decreased edema and nasal congestion. Unlike topical decongestants, pseudoephedrine is administered systemically and does not cause rebound congestion with appropriate use.
Indications
- Temporary relief of nasal congestion due to common cold
- Relief of nasal congestion due to hay fever or other upper respiratory allergies
- Relief of sinus congestion and pressure
- Adjunctive therapy for eustachian tube congestion
Dosage and Administration
Adults and children ≥12 years:- Immediate-release: 60 mg every 4-6 hours
- Maximum: 240 mg in 24 hours
- Extended-release: 120 mg every 12 hours
- 30 mg every 4-6 hours
- Maximum: 120 mg in 24 hours
- 15 mg every 4-6 hours
- Maximum: 60 mg in 24 hours
- Renal impairment: Use with caution; consider reduced dosing
- Hepatic impairment: Use with caution
- Elderly: May be more sensitive to effects; consider lower doses
Pharmacokinetics
Absorption: Well absorbed from gastrointestinal tract Distribution: Widely distributed throughout body; crosses blood-brain barrier and placenta Metabolism: Partially metabolized in liver by N-demethylation Elimination: Primarily excreted unchanged in urine (70-90%); elimination half-life: 9-16 hours Onset of action: 30 minutes Duration of action: 4-6 hours (immediate-release); 12 hours (extended-release)Contraindications
- Hypersensitivity to pseudoephedrine or any component of the formulation
- Severe hypertension
- Severe coronary artery disease
- Concurrent MAO inhibitor use (within 14 days)
- Uncontrolled hyperthyroidism
- Closed-angle glaucoma
- Urinary retention
Warnings and Precautions
- Use with caution in patients with:
- Hypertension - Diabetes mellitus - Ischemic heart disease - Hyperthyroidism - Prostatic hypertrophy - Increased intraocular pressure
- May cause CNS stimulation and insomnia
- Risk of medication misuse due to stimulant properties
- Not recommended during pregnancy (Category C) unless potential benefit justifies potential risk
- Use caution when driving or operating machinery due to potential dizziness or nervousness
Drug Interactions
MAO inhibitors: Risk of hypertensive crisis Beta-blockers: Potential for hypertension and bradycardia Other sympathomimetic agents: Additive effects and increased risk of adverse reactions Antihypertensive medications: May decrease effectiveness Theophylline: Increased risk of CNS stimulation Digoxin: Increased risk of cardiac arrhythmiasAdverse Effects
Common (≥1%):- Nervousness
- Restlessness
- Insomnia
- Headache
- Dizziness
- Tachycardia
- Palpitations
- Dry mouth
- Nausea
- Severe hypertension
- Cardiac arrhythmias
- Seizures
- Hallucinations
- Allergic reactions including anaphylaxis
- Ischemic colitis
- Rhabdomyolysis
Monitoring Parameters
- Blood pressure (especially in hypertensive patients)
- Heart rate and rhythm
- Signs of CNS stimulation
- Relief of nasal congestion symptoms
- Adverse effects (particularly cardiovascular and CNS effects)
- Signs of misuse or abuse
Patient Education
- Take as directed; do not exceed recommended dosage
- Immediate-release tablets may be taken with or without food
- Extended-release tablets should be swallowed whole; do not crush or chew
- May cause nervousness, dizziness, or sleeplessness
- Avoid caffeine-containing products as they may increase nervousness
- Consult healthcare provider if symptoms do not improve after 7 days or are accompanied by fever
- Seek immediate medical attention if experiencing chest pain, rapid heartbeat, severe headache, or nervousness
- Store at room temperature away from moisture and heat
- Be aware of purchase restrictions due to methamphetamine production concerns
References
1. FDA. (2020). Sudafed (pseudoephedrine hydrochloride) prescribing information. 2. Simons FER, Simons KJ. (2011). Decongestants, antihistamines, and cold remedies. In: Middleton's Allergy: Principles and Practice, 8th ed. 3. Hatton RC, et al. (2007). Pseudoephedrine and the risk of ischemic stroke. Neurology. 4. Eccles R. (2006). Mechanisms of the placebo effect of sweet cough syrups. Respiratory Physiology & Neurobiology. 5. Horak F, et al. (2006). Effect of pseudoephedrine in nasal patency. Allergy. 6. American College of Chest Physicians. (2006). Evidence-based guidelines for the treatment of upper respiratory tract infections. 7. Clinical Pharmacology [Internet]. Tampa (FL): Elsevier. Pseudoephedrine. 8. Micromedex Solutions. Pseudoephedrine. Truven Health Analytics. 9. National Institute on Drug Abuse. (2021). Methamphetamine. 10. Lexicomp Online. Pseudoephedrine. Wolters Kluwer Health.