Respiratory Pharmacology Review

Summary

This video provides an in-depth explanation of common over-the-counter medications for treating allergies, asthma, and related conditions. It covers antihistamines, decongestants, glucocorticoids, and cough medications, explaining their mechanisms, side effects, and recommended use. Key highlights include the difference between first and second-generation antihistamines, the role of sympathomimetic decongestants, and the types of inhalers used for asthma management. The video also addresses the importance of preventing allergic symptoms and highlights some of the newer biologic treatments, such as Omalizumab, for allergy-related asthma. It provides practical advice on medication use and side effects for both seasonal and chronic allergy sufferers.

Takeaways

• 😀 First-generation antihistamines like Benadryl (diphenhydramine) block H1 receptors to treat allergies but come with common side effects like sedation, dry mouth, and urinary retention.
• 😀 Antihistamines are most effective when taken before allergy symptoms appear, and seasonal allergy sufferers should take them daily to prevent histamine effects.
• 😀 Second-generation antihistamines (e.g., Zyrtec, Claritin) are less likely to cross the blood-brain barrier, leading to fewer side effects, especially CNS-related issues.
• 😀 Decongestants, such as pseudoephedrine (Sudafed), act as sympathomimetics, causing vasoconstriction in the nasal passages, but they should be avoided in patients with hypertension.
• 😀 Rebound congestion is a common issue with nasal decongestant sprays, and they should not be used for more than 3-5 days to avoid worsening symptoms.
• 😀 Glucocorticoid nasal sprays (e.g., Nasacort, Flonase) are effective for treating allergic rhinitis and have fewer systemic side effects compared to oral steroids.
• 😀 Cough medications like Mucinex and Robitussin combine an expectorant (guaifenesin) with a cough suppressant (dextromethorphan) to break up chest congestion.
• 😀 Asthma medications target two main issues: inflammation and bronchoconstriction. Oral steroids like methylprednisolone and prednisone are used for asthma exacerbations.
• 😀 Inhalers come in various types, including metered-dose inhalers, dry powder inhalers, and nebulizers, each with unique delivery methods for asthma medications.
• 😀 Combination inhalers like Symbicort and Advair combine inhaled steroids with long-acting beta agonists (LABAs) to target both inflammation and bronchoconstriction in asthma and COPD treatment.

Q & A

What causes allergies in the body?

Allergies occur when the body is exposed to allergens like pollen, pet dander, or dust. This exposure triggers the immune system to release histamine, which causes the typical allergic reactions.

How do antihistamines work in treating allergies?

Antihistamines work by blocking H1 receptors, which histamine usually binds to. By blocking these receptors, antihistamines prevent the effects of histamine, such as vasodilation, itching, and mucus secretion.

What is the difference between first-generation and second-generation antihistamines?

First-generation antihistamines, like Benadryl (diphenhydramine), tend to cross the blood-brain barrier and can cause more central nervous system side effects like sedation and confusion. Second-generation antihistamines, like Zyrtec (cetirizine) and Claritin (loratadine), are less likely to cross into the brain and have fewer side effects.

What are common side effects of first-generation antihistamines?

First-generation antihistamines are known for their anticholinergic side effects, which can include dry mouth, blurred vision, urinary retention, constipation, tachycardia, and confusion. These effects are remembered using the acronym 'ABDUCT.'

Why should decongestants be avoided by people with hypertension?

Decongestants, such as pseudoephedrine, work by activating alpha-1 receptors to cause vasoconstriction. This can increase blood pressure and exacerbate cardiovascular issues, which is why they should be avoided in people with hypertension.

What is rebound congestion, and how can it be avoided when using nasal decongestants?

Rebound congestion occurs when nasal decongestant sprays are used for too long (more than 3-5 days), causing the congestion to worsen. To avoid this, patients should limit their use and gradually switch to glucocorticoid nasal sprays, which are effective for longer-term relief.

What are glucocorticoid nasal sprays used for, and what are their side effects?

Glucocorticoid nasal sprays, such as Nasacort (triamcinolone) and Flonase (fluticasone), are used to treat allergic rhinitis. Their side effects include a burning or itching sensation in the nose, dryness, sore throat, nosebleeds, and headaches, but they are less likely to cause systemic effects compared to oral steroids.

How do mucolytics and expectorants work to treat chest congestion?

Mucolytics and expectorants, like guaifenesin, help loosen and clear mucus from the respiratory tract. Guaifenesin works by increasing the flow of respiratory tract secretions, which helps break up chest congestion.

How are inhaled medications used in asthma treatment?

Inhaled medications for asthma are designed to target inflammation and bronchoconstriction. These include inhalers like metered dose inhalers (MDIs), dry powder inhalers, and nebulizers, each delivering medication in different ways, depending on the patient’s needs.

Why must patients with asthma rinse their mouth after using inhaled steroids?

Patients must rinse their mouth after using inhaled steroids to prevent oral thrush (fungal infection) and reduce throat irritation or hoarseness, which are common side effects of glucocorticoid inhalers.