Anti allergic drugs used in ENT
I'll start by reading the medical library skill, then search for anti-allergic drugs used in ENT practice.
Reading File
Now let me search the medical library for anti-allergic drugs in ENT context.
Finding Sources
Finding Sources
Excellent results. Now let me read the most relevant ENT-specific sections in parallel.
Reading File
Reading File
Reading File
Let me now read the detailed drug sections from KJ Lee's Essential Otolaryngology and more from Cummings.
Reading File
Reading File
I now have comprehensive information. Let me also read the KJ Lee section on antihistamines and oral decongestants for completeness.
Reading File
I now have rich, comprehensive information from multiple ENT textbooks. Let me compile the full answer.
Anti-Allergic Drugs Used in ENT
Allergic conditions in ENT practice - primarily allergic rhinitis, allergic otitis, urticaria, and angioedema - are managed with a stepwise pharmacological approach. Below is a systematic classification.
1. Antihistamines (H1 Receptor Antagonists)
The backbone of anti-allergic therapy. They block H1 receptors, reducing itching, sneezing, and rhinorrhea. Classified into two generations:
First-Generation (Sedating)
| Drug | Notes |
|---|---|
| Diphenhydramine | Highly sedating; significant anticholinergic effects |
| Chlorpheniramine | Most commonly used; moderate sedation |
| Promethazine | Strong antiemetic + antihistamine; useful in vertigo/vestibular allergy |
| Hydroxyzine | Useful in urticaria and pruritus |
| Cyclizine / Meclizine | Used in vestibular disorders and motion sickness in ENT |
- Cross the blood-brain barrier readily
- Significant anticholinergic side effects (dry mouth, urinary retention, constipation)
- Tachyphylaxis can develop
- Avoid in patients performing skilled tasks (pilots, drivers)
Second-Generation (Non-Sedating)
| Drug | Notes |
|---|---|
| Loratadine | Lipophobic; minimal CNS effects; OTC |
| Fexofenadine | Least sedating; no QTc prolongation; safe in cardiac patients |
| Cetirizine | Slightly sedating at higher doses; fast onset |
| Desloratadine | Active metabolite of loratadine; potent |
| Levocetirizine | R-enantiomer of cetirizine; highly potent |
- Lipophobic - do not cross the BBB readily
- Little to no anticholinergic activity
- Safe in asthma patients
- Metabolized by CYP3A4 - be aware of CYP3A4 inhibitors (e.g., erythromycin, ketoconazole)
- Little tachyphylaxis; strongly recommended for allergic rhinitis
Topical (Intranasal) Antihistamines
| Drug | Notes |
|---|---|
| Azelastine | Most commonly used; rapid onset; as effective or superior to oral antihistamines for nasal congestion |
| Olopatadine | Available for nasal and ocular use |
- Work directly at target organ (nose, eyes)
- At least as effective as intranasal corticosteroids for sneezing, itching, rhinorrhea, and ocular symptoms
- Best used in combination with intranasal corticosteroids (not as monotherapy)
Key Point (Cummings Otolaryngology): "The most effective combination for the treatment of allergic rhinitis is an intranasal steroid with an intranasal antihistamine."
2. Intranasal Corticosteroids (First-Line Therapy)
The most effective class for allergic rhinitis - superior to antihistamines and leukotriene receptor antagonists for controlling nasal inflammation.
| Drug | Notes |
|---|---|
| Fluticasone propionate | Low systemic bioavailability; onset within 12 hours; aqueous spray |
| Fluticasone furoate | More potent; once daily; very low bioavailability |
| Mometasone furoate | Very low systemic absorption; approved from age 2 |
| Budesonide | Only intranasal steroid with Pregnancy Category B; aqueous, scent-free |
| Triamcinolone acetonide | Available OTC in the US; aqueous spray |
| Beclomethasone dipropionate | Older agent; higher systemic bioavailability; may cause growth suppression in children |
| Ciclesonide | Prodrug activated locally; minimal systemic effects |
| Flunisolide | Significant systemic bioavailability; poorly tolerated due to propylene glycol base |
Key points:
- First-line therapy for allergic rhinitis (except mildest cases)
- Start 2 weeks before pollen season
- Daily dosing more efficacious than as-needed dosing
- Side effects: epistaxis, nasal dryness, local irritation; rare septal perforation
- Aim spray away from the nasal septum
- Newer agents generally free of HPA axis suppression
- May have a negative effect on short-term growth in children - use the lowest effective dose
3. Leukotriene Receptor Antagonists (LTRAs)
Block leukotriene receptors on target cells, reducing nasal congestion, rhinorrhea, and sneezing.
| Drug | Notes |
|---|---|
| Montelukast | Only agent approved for allergic rhinitis; also for asthma and exercise-induced bronchospasm; approved from 6 months of age |
| Zafirlukast | Used in asthma; less evidence in rhinitis |
- Efficacy parallels antihistamines but inferior to intranasal corticosteroids
- Particularly useful in patients with concurrent asthma (unified airway disease)
- Not recommended as monotherapy or first-line for allergic rhinitis
- Can be second-line or when intranasal corticosteroids are contraindicated
4. Mast Cell Stabilizers
| Drug | Mechanism | Notes |
|---|---|---|
| Cromolyn sodium (Sodium cromoglicate) | Stabilizes mast cell membranes; inhibits degranulation and histamine release | Lipophobic; no systemic absorption; must be given 3-4x/day; best used prophylactically before allergen exposure; inferior to intranasal corticosteroids |
| Ketotifen | Mast cell stabilizer + H1 antagonist | Used as eye drops for allergic conjunctivitis |
- Will not treat symptoms once mast cells have already degranulated
- Compliance is difficult due to frequent dosing
- Consider in patients who cannot tolerate intranasal corticosteroids
- Free of systemic adverse effects (no systemic absorption)
5. Decongestants
Reduce nasal congestion by alpha-adrenergic vasoconstriction; have minimal effect on rhinorrhea, itching, or sneezing.
Oral Decongestants
| Drug | Notes |
|---|---|
| Pseudoephedrine | Alpha-2 agonist; effective; controlled availability (precursor to methamphetamine) |
| Phenylephrine | Not superior to placebo in clinical trials; not recommended |
- Side effects: hypertension, insomnia, tachycardia, arrhythmia, anorexia
- Often combined with antihistamines (e.g., loratadine + pseudoephedrine)
Topical Decongestants
| Drug | Notes |
|---|---|
| Oxymetazoline | Imidazoline; very effective; rebound congestion (rhinitis medicamentosa) if used >3-5 days |
| Xylometazoline | Similar to oxymetazoline |
| Naphazoline | Older agent; significant rebound |
| Tetrahydrozoline | Primarily used as eye drops |
- Do not use for more than 3-5 days - risk of rebound congestion (rhinitis medicamentosa)
6. Intranasal Anticholinergics
| Drug | Notes |
|---|---|
| Ipratropium bromide | Decreases watery nasal secretions from seromucous glands; used for rhinorrhea in allergic and non-allergic rhinitis; needs 6x/day dosing due to short half-life |
- Useful as adjuvant therapy in patients with persistent rhinorrhea despite intranasal corticosteroid use
- Combination with intranasal corticosteroids more effective than either alone
7. Systemic Corticosteroids
- Used for short courses in severe allergic inflammation only
- Prednisone, methylprednisolone, dexamethasone
- Oral preferred over parenteral for allergic rhinitis
- Not recommended for routine use - largely replaced by intranasal steroids
- Effects noticed within 12-24 hours
8. Biologics
| Drug | Mechanism | Notes |
|---|---|---|
| Omalizumab | Humanized anti-IgE monoclonal antibody | Not FDA-approved for allergic rhinitis; approved for chronic urticaria and asthma; superior to immunotherapy alone when combined; costs ~$18,000/year |
| Dupilumab | IL-4/IL-13 receptor antagonist | Approved for chronic rhinosinusitis with nasal polyps (CRSwNP) |
| Mepolizumab / Benralizumab | Anti-IL-5 / anti-IL-5R | Eosinophilic disease; nasal polyps |
9. Immunotherapy (Disease-Modifying)
The only treatment that alters the natural course of allergic disease.
- Subcutaneous Immunotherapy (SCIT) - conventional allergy shots
- Sublingual Immunotherapy (SLIT) - sublingual drops or tablets
"Immunotherapy is the most effective treatment of allergic rhinitis." - Cummings Otolaryngology Head and Neck Surgery
Summary: Hierarchical Treatment Approach
Mild Intermittent AR:
→ Oral/intranasal antihistamine ± decongestant
Moderate-Severe or Persistent AR:
→ Intranasal corticosteroid (FIRST-LINE)
→ Add intranasal antihistamine (most effective combination)
→ Add montelukast if concurrent asthma
Persistent rhinorrhea:
→ Add intranasal ipratropium bromide
Prophylaxis before allergen season:
→ Start INCS 2 weeks early; consider cromolyn sodium
Disease modification:
→ Allergen immunotherapy (SCIT or SLIT)
Severe/refractory/CRSwNP:
→ Biologics (omalizumab, dupilumab)
Sources:
- Cummings Otolaryngology Head and Neck Surgery, Chapter 35
- KJ Lee's Essential Otolaryngology, Chapter on Treatment of Allergy
- Scott-Brown's Otorhinolaryngology Head & Neck Surgery, Vol 1
This is a shared conversation. Sign in to Orris to start your own chat.