Decongestants

• Definition and Mechanism of Action

  • Decongestants are medications that decrease the overproduction of secretions in the upper respiratory tract.

  • They achieve this by causing local vasoconstriction, which leads to:

  • Shrinking of swollen mucous membranes.

  • Opening of clogged nasal passages, providing relief from discomfort.

  • Promoting drainage of secretions and improving airflow.

  • An adverse effect of frequent or prolonged use is rebound congestion, technically termed rhinitis medicamentosa.

  • This condition occurs because the reflex reaction to vasoconstriction leads to rebound vasodilation.

  • It can cause prolonged overuse of decongestants.

• Types of Decongestants

  • Decongestants are primarily classified as adrenergics or sympathomimetics.

  • Other forms include topical steroids, which are used in chronic rhinitis but take several weeks to be effective.

Topical Nasal Decongestants

• Common Agents

  • Examples of topical nasal decongestants include:

  • Naphazoline (Privine)

  • Oxymetazoline (Afrin and others)

  • Phenylephrine (Coricidin and numerous others)

  • Tetrahydrozoline (Tyzine)

  • Xylometazoline (Otrivin)

  • Many of these medications are available over-the-counter (OTC).

  • The choice of a topical decongestant is often personal; some patients may respond well to one medication but not to another.

Therapeutic Actions and Indications

• Action Mechanism

  • Topical decongestants are classified as sympathomimetics, which imitate the effects of the sympathetic nervous system.

  • They cause vasoconstriction, leading to:

  • Decreased edema and inflammation of nasal membranes.

  • Common indications for use include:

  • Relief from nasal congestion due to common cold, sinusitis, and allergic rhinitis.

  • Facilitation of nasal dilation for medical examinations or relief of otitis media discomfort.

Patient and Family Teaching

• Administration Techniques

  • Proper administration techniques are crucial for effective nasal drug delivery:

  • Instruct patients to sit upright.

  • Press a finger over one naris to close it while placing the tip of the spray bottle about half an inch into the open naris.

  • Hold the bottle upright and firmly squeeze to deliver the medication.

  • Repeat for the other naris.

  • Advise patients not to blow their nose immediately after administration to avoid expelling the medication.

Pharmacokinetics

• Onset and Absorption

  • Due to topical application, the onset of action is almost immediate with minimized chances of systemic effects.

  • Any portion absorbed is metabolized in the liver and excreted in urine.

Contraindications and Cautions

• General Precautions

  • Caution is advised in cases of lesions or erosion in mucous membranes, which may facilitate systemic absorption.

  • Patients with conditions worsened by sympathetic activity require careful monitoring; this includes patients with:

  • Glaucoma

  • Hypertension

  • Diabetes

  • Thyroid disease

  • Coronary disease

  • Prostate problems

  • There are no available studies on the effects of these topical decongestants during pregnancy or lactation, thus caution is recommended.

Adverse Effects

• Common Adverse Effects

  • Local burning and stinging, particularly in the initial uses.

  • If irritation persists, the medication should be discontinued due to potential mucous membrane lesions.

  • Extended use (longer than 3 to 5 days) may cause rebound congestion (rhinitis medicamentosa), creating a cycle of congestion and increased drug use.

  • Sympathomimetic adverse effects may include:

  • Increased pulse and blood pressure

  • Urinary retention

Clinically Important Drug-Drug Interactions

• Monitor cautions for concurrent use with other medications affecting the sympathetic nervous system.

Prototype Summary: Tetrahydrozoline

• Indications

  • Symptomatic relief for nasal and nasopharyngeal congestion due to:

  • The common cold

  • Hay fever

  • Other respiratory allergies

• Actions

  • Sympathomimetic effects through norepinephrine release; results in vasoconstriction and decreased nasal edema and inflammation.

• Pharmacokinetics

  • Route: Topical (nasal spray)

  • Peak: 5-10 minutes

  • Duration: 6-10 hours

  • Half-life: Unknown; undergoes liver metabolism and is minimally systemic during absorption.

• Adverse Effects

  • Disorientation

  • Confusion

  • Light-headedness

  • Nausea and vomiting

  • Fever

  • Dyspnea

  • Rebound congestion

Oral Decongestants

• Available Agents

  • Oral decongestants such as pseudoephedrine and phenylephrine (Sudafed and others).

Therapeutic Actions and Indications

• Action Mechanism

  • Oral decongestants are taken to decrease nasal congestion due to common cold, sinusitis, and allergic rhinitis.

  • They help alleviate otitis media by promoting drainage of the eustachian tube.

  • These drugs work by stimulating alpha-adrenergic receptors in the nasal mucous membrane, which results in shrinkage of the membrane and improved airflow.

Pharmacokinetics

• Absorption and Distribution

  • Pseudoephedrine is typically well absorbed, achieving peak levels within 20 to 45 minutes.

  • It is metabolized in the liver and primarily excreted in urine.

  • Phenylephrine is available both in nasal spray and combination products.

Contraindications and Cautions

• Similar cautions as topical decongestants apply due to adrenergic properties affecting various health conditions that may exacerbate with sympathetic activity.

Adverse Effects

• Common Side Effects

  • Rebound congestion

  • Increased anxiety, tenseness, restlessness, and tremors.

  • Hypertension and arrhythmias can occur due to systemic absorption.

  • There are safety measures for pseudoephedrine to limit misuse for methamphetamine production.

Clinically Important Drug-Drug Interactions

• Many OTC and combination products may contain pseudoephedrine or phenylephrine.

  • Concurrent use can lead to serious adverse effects; thus, patients should be informed on reading labels carefully.

Prototype Summary: Pseudoephedrine

• Indications

  • Temporary relief of nasal congestion from:

  • The common cold

  • Hay fever

  • Sinusitis

  • Relief of eustachian tube congestion.

• Actions

  • Produces sympathomimetic effects; causes vasoconstriction in nasal passages to promote drainage and improve ventilation.

Steroid Nasal Decongestants

• Common Agents

  • Includes:

  • Beclomethasone (Beconase AQ)

  • Budesonide (Rhinocort)

  • Flunisolide (generic)

  • Fluticasone (Flonase Allergy Relief)

  • Triamcinolone (Nasacort Allergy 24 Hour)

Therapeutic Actions and Indications

• Used primarily for allergic rhinitis treatment and to reduce inflammation following nasal polyp removal.

• Recognized as first-line medications for nasal congestion.

Pharmacokinetics

• Onset of Action

  • Not immediate; changes may take up to 1 week, and should be discontinued if no effects are seen after 3 weeks.

• Absorption

  • Generally, these drugs are not absorbed systemically, with pharmacokinetics similar to other steroids if absorbed.

Contraindications and Cautions

• Contraindicated in the presence of acute infections (e.g., tuberculosis) due to the blockade of inflammatory responses.

• Increased risk of Candida infections reported.

• Caution during pregnancy and lactation due to minimal systemic absorption.

Adverse Effects

• Localized burning, irritation, stinging, dry mucosa, and headaches.

• Special caution for patients recovering from nasal surgery or trauma due to delayed healing from steroid use.

Clinically Important Drug-Drug Interactions

• Topically applied, hence minimal interaction with systemic medications; consult healthcare providers for concurrent nasal medications.

Prototype Summary: Flunisolide

• Indications

  • Relief of symptoms from seasonal or perennial allergic/non-allergic rhinitis, and inflammation after nasal polyp removal.

• Actions

  • Exhibits anti-inflammatory action that results from direct local effects blocking inflammatory response.