What are the types of oral decongestants for treating nasal congestion?

Types of Oral Decongestants for Treating Nasal Congestion

The main types of oral decongestants for treating nasal congestion are pseudoephedrine and phenylephrine, with pseudoephedrine being significantly more effective due to better oral bioavailability compared to phenylephrine, which is extensively metabolized in the gut. 1

Pseudoephedrine

• Functions as an α-adrenergic agonist that reduces nasal congestion by causing vasoconstriction in the nasal passages 1
• Available in immediate-release (30-60 mg every 4-6 hours) and extended-release formulations 1
• Demonstrated superior efficacy for nasal decongestion in clinical trials using both objective measures of nasal airway resistance and subjective symptom scores 2
• Subject to sales restrictions in the United States (kept behind pharmacy counter) due to its potential use in methamphetamine production 1
• FDA-approved for temporarily relieving nasal congestion due to common cold, hay fever, and other upper respiratory allergies 3

Side Effects and Precautions with Pseudoephedrine

• Associated with small increases in systolic blood pressure (0.99 mmHg) and heart rate (2.83 beats/min) but generally no significant effect on diastolic blood pressure 1
• May cause insomnia, loss of appetite, irritability, tremor, palpitations, and sleep disturbance 1
• Should be used with caution in patients with hypertension, arrhythmias, angina pectoris, coronary artery disease, cerebrovascular disease, hyperthyroidism, and glaucoma 1
• Generally well tolerated by most patients with controlled hypertension, but monitoring is recommended due to interindividual variation in response 1

Phenylephrine

• Also an α-adrenergic agonist that works through vasoconstriction 1
• Commonly available in 10 mg oral doses 1
• Less efficacious than pseudoephedrine as an oral decongestant due to extensive first-pass metabolism in the gut 1
• Not subject to the same sales restrictions as pseudoephedrine, making it more widely available in over-the-counter cold and cough remedies 1
• Efficacy as an oral decongestant has not been well established in clinical trials 1, 4

Phenylpropanolamine (Historical)

• Previously used as an oral decongestant but now largely withdrawn from the market 1
• Associated with more significant increases in blood pressure than pseudoephedrine (5.5 mmHg systolic and 4.1 mmHg diastolic) 1
• No longer recommended due to safety concerns 1

Clinical Application and Combination Therapy

• Oral decongestants are often combined with antihistamines for more comprehensive treatment of allergic rhinitis symptoms 5, 6
• Combination therapy with desloratadine/pseudoephedrine has shown superior efficacy in reducing nasal congestion compared to either component alone 5, 6
• Oral decongestants are appropriate for short-term use in acute conditions but not recommended for long-term daily use 1
• Pseudoephedrine is preferred over phenylephrine when maximum decongestant efficacy is needed 1, 4

Special Considerations

• Use with caution in children under 6 years of age due to risk of adverse effects including agitated psychosis, ataxia, hallucinations, and even death in rare cases 1
• Caution advised during first trimester of pregnancy due to reports of fetal heart rate changes 1
• Concomitant use with caffeine or other stimulants may increase risk of adverse effects 1
• For patients with severe nasal congestion, oral decongestants may be used alone or in combination with intranasal corticosteroids or antihistamines 7