Respiratory System Drugs Practice Questions

Q: Aminophylline inhibits which of the following enzymes?

Phosphodiesterase. ***Phosphodiesterase*** - **Aminophylline** is a methylxanthine derivative that primarily acts as a **phosphodiesterase (PDE) inhibitor** [1], [2]. - By inhibiting PDE, aminophylline increases intracellular levels of **cAMP** and **cGMP**, leading to **bronchodilation** and other effects [2], [3]. *MAO* - **MAO (monoamine oxidase)** inhibitors are antidepressants that prevent the breakdown of neurotransmitters like serotonin, norepinephrine, and dopamine. - Aminophylline does not significantly inhibit MAO. *Alcohol dehydrogenase* - **Alcohol dehydrogenase** is an enzyme responsible for metabolizing alcohol (ethanol) in the liver. - Aminophylline has no direct inhibitory effect on alcohol dehydrogenase. *Cytochrome P450* - **Cytochrome P450 (CYP450)** enzymes are a group of enzymes primarily involved in the metabolism of drugs and other xenobiotics in the liver [4]. - While aminophylline (and its active metabolite theophylline) can be metabolized by and *affect* certain **CYP450** isoenzymes (e.g., CYP1A2), it does not act as a general inhibitor of the entire CYP450 system; its primary therapeutic action is not through CYP450 inhibition.

Q: Which of the following statements is true regarding omalizumab?

All of the options. ***All of the options*** is correct because each statement is true: **Anti-IgE** - Omalizumab is a **humanized monoclonal antibody** that specifically targets and binds to **free IgE** in the circulation - By binding free IgE, it prevents IgE from attaching to **high-affinity receptors** on mast cells and basophils - This reduces the allergic cascade and prevents release of inflammatory mediators **Given subcutaneously** - Omalizumab is administered via **subcutaneous injection** only - Dosing is typically every **2 to 4 weeks** based on patient's body weight and baseline IgE levels - Not available in oral or intravenous formulations for asthma treatment **Used as add-on therapy in moderate to severe asthma prophylaxis** - FDA approved as **add-on maintenance treatment** for patients aged ≥6 years with **moderate to severe persistent allergic asthma** - Indicated when asthma is **inadequately controlled** with inhaled corticosteroids - Reduces frequency of asthma exacerbations and improves asthma control - Also approved for chronic spontaneous urticaria All three statements accurately describe omalizumab's mechanism, administration route, and clinical indication, making **"All of the options"** the correct answer.

Q: Which medication increases the efficacy of salmeterol when used together?

Corticosteroid. ***Corticosteroid*** - **Corticosteroids** act synergistically with **beta-2 agonists** like salmeterol by increasing the number and sensitivity of beta-2 receptors on bronchial smooth muscle cells. - They also reduce inflammation, which contributes to airway hyperresponsiveness, thereby improving the overall efficacy of bronchodilators. *Theophylline* - **Theophylline** is a methylxanthine that causes bronchodilation through inhibition of phosphodiesterase, but it is not directly synergistic with **salmeterol** in potentiating its primary action. - While both treat airway obstruction, their mechanisms are distinct, and theophylline has a narrow therapeutic index with significant side effects. *Ipratropium* - **Ipratropium** is an **anticholinergic bronchodilator** that blocks muscarinic receptors, leading to bronchodilation. - Its mechanism of action is different from that of **salmeterol (a beta-2 agonist)**, and while they can be used together for additive bronchodilation, ipratropium does not directly increase the efficacy of salmeterol itself. *Sodium cromoglycate* - **Sodium cromoglycate** is a **mast cell stabilizer** that prevents the release of inflammatory mediators, primarily used for asthma prophylaxis. - It does not have direct bronchodilatory effects and does not enhance the bronchodilatory action of **salmeterol**.

Q: Which of the following is NOT a mechanism of action of theophylline in bronchial asthma?

Beta-2 receptor stimulation. ***Beta-2 receptor stimulation*** - Theophylline is a **non-selective phosphodiesterase inhibitor** and an **adenosine receptor antagonist**, but it does not directly stimulate beta-2 receptors. - **Beta-2 receptor agonists** like salbutamol or formoterol are the medications that work by stimulating these receptors to cause bronchodilation. *Phosphodiesterase inhibition* - Theophylline inhibits **phosphodiesterase enzymes**, leading to an increase in intracellular **cAMP** levels. - This increase in **cAMP** promotes bronchodilation by relaxing airway smooth muscle. *Adenosine receptor antagonism* - Theophylline acts as an antagonist at **adenosine receptors**, particularly A1 and A2B. - Antagonism of adenosine receptors can reduce bronchoconstriction and inflammatory mediator release, contributing to its anti-asthmatic effects. *Increased histone deacetylation* - Theophylline, particularly at lower concentrations, increases the activity of **histone deacetylase (HDAC)**. - This action helps to **repress inflammatory gene expression**, which is a unique anti-inflammatory mechanism separate from its bronchodilatory effects.

Q: Omalizumab is primarily used in the treatment of which condition?

Asthma. ***Asthma*** - **Omalizumab** is a **monoclonal antibody** that targets and binds to **immunoglobulin E (IgE)**, preventing it from binding to mast cells and basophils. - By reducing free IgE, omalizumab helps to prevent the release of inflammatory mediators, thereby **reducing allergic reactions and asthma symptoms**, particularly in patients with severe persistent allergic asthma. *Breast carcinoma* - **Omalizumab** is not indicated for the treatment of **breast carcinoma**; treatments for breast cancer typically involve chemotherapy, radiation, surgery, and targeted therapies specific to cancer cells. - Targeted therapies for breast cancer often focus on hormone receptors (e.g., **estrogen receptor**) or growth factor receptors (e.g., **HER2**), not IgE. *Rheumatoid arthritis* - **Omalizumab** is not used for **rheumatoid arthritis (RA)**; RA is an autoimmune disease primarily involving **T-cells and cytokines** like **TNF-alpha** and **IL-6**. - Treatment for RA typically includes **DMARDs** (disease-modifying antirheumatic drugs) and **biological agents** that target specific inflammatory pathways (e.g., **adalimumab**, **etanercept**). *Chronic obstructive pulmonary disease (COPD)* - **Omalizumab** is not indicated for **COPD**, which is primarily characterized by chronic inflammation of the airways and **emphysema**, largely caused by smoking. - COPD management focuses on bronchodilators, corticosteroids, and oxygen therapy, with no role for IgE-targeting therapy.

Q: Which of the following is given in the maintenance of severe persistent asthma?

Long-acting beta 2 agonist. ***Long-acting beta 2 agonist*** - **Long-acting beta-2 agonists (LABAs)**, such as salmeterol and formoterol, are a cornerstone in the **maintenance therapy for severe persistent asthma**, providing bronchodilation for extended periods. - They are typically used in combination with **inhaled corticosteroids (ICS)** to achieve optimal asthma control and reduce the frequency of exacerbations. - LABAs should **never be used as monotherapy** for asthma; they must always be combined with ICS. *Oral Steroid* - **Oral corticosteroids** may be used as **add-on maintenance therapy** in **Step 5 severe asthma** that remains uncontrolled despite high-dose ICS-LABA combinations. - However, they are not first-line maintenance therapy due to significant **systemic side effects** with prolonged use (osteoporosis, diabetes, hypertension, adrenal suppression). - They are preferred for **short-term treatment of acute exacerbations** when used intermittently. *Ipratropium bromide* - **Ipratropium bromide** is a **short-acting anticholinergic** used primarily as a **reliever medication** in acute asthma exacerbations, particularly when beta-2 agonists are not sufficient. - It does not have a primary role in the **long-term maintenance** of severe persistent asthma, as its bronchodilatory effects are less potent and shorter-lasting than LABAs. - Long-acting anticholinergics like **tiotropium** may be used as add-on therapy in severe asthma. *Leukotriene antagonist* - **Leukotriene receptor antagonists (LTRAs)** like montelukast are used as **add-on therapy** for maintenance in persistent asthma, particularly for individuals with aspirin-induced asthma or exercise-induced bronchoconstriction. - While they contribute to asthma control, they are generally **less potent** than LABAs and inhaled corticosteroids in the management of severe persistent asthma and are not typically considered first-line maintenance monotherapy.

Q: Which opioid analgesic is used in the treatment of cough?

Codeine. ***Codeine*** - **Codeine** is a commonly used **opioid antitussive** that acts directly on the **cough center** in the medulla to suppress the cough reflex [2], [3]. - It is often found in combination with other medications in prescription and over-the-counter cough syrups [4]. *Loperamide* - **Loperamide** is an **opioid derivative** primarily used as an **antidiarrheal** agent. - It works by decreasing gut motility and fluid secretion, with minimal central nervous system penetration at therapeutic doses. *Diphenoxylate* - **Diphenoxylate** is an **opioid agonist** used in combination with atropine (as Lomotil) to treat **diarrhea**. - Its antidiarrheal action is due to decreased gastrointestinal motility and fluid secretion, and it is not primarily used for cough. *Meperidine* - **Meperidine** (also known as Pethidine) is a **synthetic opioid analgesic** primarily used for the treatment of **moderate to severe pain** [1]. - It has significant euphoric and addictive potential and is not typically used as an antitussive due to its stronger analgesic effects and side effect profile [3].

Q: Which of the following medications should be avoided in a patient with asthma?

beta-blockers. ***Correct Answer: beta-blockers*** - **Non-selective beta-blockers** can block beta-2 adrenergic receptors in the lungs, leading to **bronchoconstriction** and worsening asthma symptoms. - Even **cardioselective beta-blockers** (beta-1 selective) should be used with caution as their selectivity can be lost at higher doses. - Beta-blockers are **contraindicated** in asthma patients due to risk of severe bronchospasm. *Incorrect: theophylline* - **Theophylline** is a bronchodilator used in asthma management, particularly for **nocturnal symptoms** or as add-on therapy. - It works by inhibiting phosphodiesterase, increasing intracellular cAMP, which leads to **smooth muscle relaxation**. *Incorrect: corticosteroids* - **Corticosteroids** (inhaled or systemic) are a cornerstone in asthma management due to their potent **anti-inflammatory effects**. - They reduce airway inflammation, reduce **bronchial hyperresponsiveness**, and decrease the frequency and severity of asthma exacerbations. *Incorrect: sympathomimetic amines* - Many **sympathomimetic amines**, such as **beta-2 agonists** (e.g., albuterol, salmeterol), are primary bronchodilators used in asthma. - They work by stimulating beta-2 adrenergic receptors in the airway smooth muscle, leading to **bronchodilation**.

Q: All of the following are expectorants except:

Noscapine. ***Noscapine*** - **Noscapine** is an **antitussive** (cough suppressant) that works by suppressing the **cough reflex** in the brainstem, with no expectorant properties. - It is an **opium alkaloid** derivative but lacks significant analgesic or addictive effects. *Hypertonic saline* - **Hypertonic saline** is used as an **expectorant** to induce sputum production by drawing water into the airways through osmosis, thinning mucus. - It works by irritating the airways, leading to a reflexive increase in mucus secretion and clearance. *Guaifenesin* - **Guaifenesin** is a well-known **expectorant** that works by increasing the volume and reducing the viscosity of respiratory tract secretions. - This helps to facilitate the removal of mucus from the airways by making coughs more productive. *Ammonium chloride* - **Ammonium chloride** acts as a **systemic expectorant** by irritating the bronchial mucosa, which reflexively increases the secretion of respiratory fluids. - It is thought to thin the mucus, making it easier to expel.

Q: Which is the most common side effect of inhaled beclomethasone dipropionate?

Oropharyngeal candidiasis. ***Oropharyngeal candidiasis*** - Inhaled corticosteroids like **beclomethasone dipropionate** can suppress the local immune response in the oral cavity. - This immunosuppression creates an environment conducive to the overgrowth of *Candida albicans*, leading to **thrush**. *Pneumonia* - While inhaled corticosteroids can slightly increase the risk of pneumonia in some populations (e.g., COPD patients), it is **not the most common** side effect. - **Oropharyngeal candidiasis** is much more frequently encountered. *Atrophic rhinitis* - This condition involves inflammation and thinning of the nasal lining, often associated with chronic infections or surgery. - It is **not a typical or common side effect** of inhaled corticosteroids. *Pituitary adrenal suppression* - Systemic absorption of high doses of inhaled corticosteroids can lead to **adrenal suppression**, but this is a **less common and more serious** side effect, usually seen with prolonged high-dose use. - **Oropharyngeal candidiasis** is a local effect and far more prevalent.

Question 1

Aminophylline inhibits which of the following enzymes?

Accepted Answer

Phosphodiesterase

Answer

MAO

Answer

Alcohol dehydrogenase

Answer

Cytochrome P450

Question 2

Which of the following statements is true regarding omalizumab?

Accepted Answer

All of the options

Answer

Anti-IgE

Answer

Given subcutaneously

Answer

Used as add-on therapy in moderate to severe asthma prophylaxis

Question 3

Which medication increases the efficacy of salmeterol when used together?

Accepted Answer

Corticosteroid

Answer

Theophylline

Answer

Ipratropium

Answer

Sodium cromoglycate

Question 4

Which of the following is NOT a mechanism of action of theophylline in bronchial asthma?

Accepted Answer

Beta-2 receptor stimulation

Answer

Adenosine receptor antagonism

Answer

Increased histone deacetylation

Answer

Phosphodiesterase inhibition

Question 5

Omalizumab is primarily used in the treatment of which condition?

Accepted Answer

Asthma

Answer

Breast carcinoma

Answer

Rheumatoid arthritis

Answer

Chronic obstructive pulmonary disease (COPD)

Question 6

Which of the following is given in the maintenance of severe persistent asthma?

Accepted Answer

Long-acting beta 2 agonist

Answer

Oral Steroid

Answer

Ipratropium bromide

Answer

Leukotriene antagonist

Question 7

Which opioid analgesic is used in the treatment of cough?

Accepted Answer

Codeine

Answer

Loperamide

Answer

Diphenoxylate

Answer

Meperidine

Question 8

Which of the following medications should be avoided in a patient with asthma?

Accepted Answer

beta-blockers

Answer

theophylline

Answer

corticosteroids

Answer

sympathomimetic amines

Question 9

All of the following are expectorants except:

Accepted Answer

Noscapine

Answer

Guaifenesin

Answer

Ammonium chloride

Answer

Hypertonic saline

Question 10

Which is the most common side effect of inhaled beclomethasone dipropionate?

Accepted Answer

Oropharyngeal candidiasis

Answer

Pneumonia

Answer

Atrophic rhinitis

Answer

Pituitary adrenal suppression

Respiratory System Drugs — MCQs

Respiratory System Drugs — MCQs

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