Respiratory System

Question 1

Antihistamines (H1-receptor antagonists)

Answer 1

M: H1 antagonism
I: Allergies e.g. Hay fever, pruritus and urticaria, adjunct for anaphylaxis
C: Sedating antihistamines should be avoided in severe liver disease as may precipitate hepatic encephalopathy
A: Sedation

Cetirizine, loratidine, fexofenadine, Chlorphenamine

Question 2

Antimuscarinics, Bronchodilators

Answer 2

M: Competitive inhibitor of acetylcholine, reduces smooth muscle tone and reduces secretions.
I: COPD and Asthma
C: Angle-closure glaucoma, arrhythmias or urinary retention
A: Irritation of the respiratory tract with nasapharyngitis, sinusitis and cough, GI disturbance - dry mouth, constipation, urinary retention, blurred vision and headaches.

Ipratropium, tiotropium, glycopyrronium, acildinium

Question 3

B2 Agonists

Answer 3

M: G couple receptor activation to cause Smooth muscle relaxation, stimulation of Na+/K+ adenosine triphosphatase (ATPase) pumps causing shift of K+ from the extracellular to the intracellular compartment therefore useful adjunct in hyperkalaemia.
I: Asthma, COPD, Hyperkalaemia
C: Cardiovascular disease
A: Tachycardia, palpitations, anxiety and tremor. Also cause muscle cramps.

Salbutamol, terbutaline, salmeterol, formoterol, indacaterol

Question 4

Corticosteroids (glucocorticoids), inhaled

Answer 4

M: Down regulation of pro-inflammatory interleukins, cytokines and cheekiness with up regulation of anti inflammatory proteins in the airways, the reduces mucosal inflammation, widens the airways and reduces mucus secretion. This improves symptoms and reduce exacerbations in asthma and COPD.
I: Asthma and COPD
C: History of pneumonia and children
A: Oral candidiasis, horse voice and pneumonia.

Beclomethasone, budesonide, fluticasone

Question 5

Leukotriene receptor antagonists

Answer 5

M: Block G protein-coupled leukotriene receptor CysLT1, therefore reducing inflammation and bronchoconstriction
I: Adults as add on therapy for asthma, children 5-12yrs as alternative to LABA, children under 5 as first line preventative therapy if unable to take inhaled corticosteroids
C: Not to be used unless asthma incompletely controlled by corticosteroids and long-acting B2 agonists.
A: Headache, abdo pain, hyperactivity, reduced ability to concentrate and Churg-Strauss syndrome.

Montelukast

Question 6

Oxygen

Answer 6

M: Increases delivery of oxygen to tissues, accelerated the diffusion of nitrogen out of the body, shortens the half life of carboxyhaemoglobin.
I: Acute hypoxaemia, pneumothorax, CO poisoning
C: Chronic type 2 reps failure, heat source of naked flame
A: Discomfort of a face mask, dry throat or hyperoxaemia may be harmful

Question 7

Phosphodiesterase (type 5) inhibitors

Answer 7

M: Selective for PDE type 5 (PDE-5). Sildenafil increases cGMP contractions, improving penile blood flow and erection quality. Also causes arterial vasodilatation.
I: Erectile dysfunction, primary pulmonary hypertension
C: Stroke, acute coronary syndrome, cardiovascular disease, hepatic or renal impairment
A: Do not use with drugs that increase NO e.g. nitrates or nicorandil. Use with caution of patients taking vasodilators and cytochrome p450 inhibitors.

Sildenafil