Pharmacology Test 1

Drugs for Autonomic Nervous System, Asthma, COPD, Hypertension, Heart Failure, Arrhythmia, Dyslipidaemia, Thrombosis and Antimicrobials

Oxymetazoline

Indication: Nasal Congestion

• Caused by swelling of blood vessels in the nose.

Class: α₁ agonists

MOA: Stimulates α₁ receptors in the nasal vasculature, causing vasoconstriction. This helps to relieve congestion.

Other: Delivery Intranasal (Nasal Spray)

Adverse Effects:

• Increased blood pressure: excess vasoconstriction caused by unselective binding to α₁ receptors. Does not occur often as it is delivered via nasal spray.

• Rebound congestion: excess use causes down regulation of α₁ receptors in the nasal vasculature, increasing vasodilation when stopping use.

Prazosin

Indication: Hypertension, Benign Prostatic Hyperplasia (difficulty urinating)

Class: α₁ antagonist

MOA: Inhibits α₁ receptor activation, which:

• Inhibits vasoconstriction, causing vessels to be dilated, lowering blood pressure.

• Inhibits sphincter contraction in the bladder, improving urine flow.

Adverse Effects:

• Hypotension: dilation of blood vessels may cause blood pressure to drop.

• Nasal Congestion: dilation of nasal blood vessels may cause congestion.

Salbutamol

Indication: Asthma & COPD (Airway obstruction and narrowing)

Class: β₂ agonist

• Short Acting β₂ agonist. Is a reliever medication which has a rapid onset of effects with a short duration.

Other: used in combination with Ipratropium and Tiotropium in COPD.

MOA: Stimulates β₂ receptors, causing relaxing of bronchial smooth muscle, causing bronchodilation. This helps to improve airflow into and out of the lungs, assisting both asthma and COPD.

Adverse Effects:

• Tremor: activation of β₂ receptors can trigger smooth muscle contraction.

• Palpitations and Tachycardia: activation of β₂ receptors can trigger cardiac muscle contraction, increasing heart rate and contractility.

• Hyperglycaemia: activation of β₂ receptors can trigger glyconeogenesis in skeletal muscles and the liver, causing excess glucose in the blood.

Propranolol

Indication: Hypertension (High Blood Pressure)

Class: Beta Blocker

• Non-Selective: is an antagonist for both β₁ and β₂.

MOA: Prevents activation of β₁ and β₂ receptors in:

• The heart, inhibiting increases in heart rate and contractility, reducing BP.

• The kidneys: decreases renin secretion which reduces water retention and vessel constriction, reducing BP.

Adverse Effects:

• Blocking β₂ receptors in the lungs prevents bronchodilation, meaning it should not be used in those with pre-existing lung condition.

• Blocking β₂ receptors in the liver and skeletal muscles prevents control of blood glucose levels. Causes vasodilation to skeletal muscles, causing cold extremities.

• Blocking β₂ receptors in the bladder prevents sphincter contraction, contributing to incontenence, loss of bladder control.

• Lipophilic beta blockers can pass the blood-brain barrier, causing sedation or feeling tired.

Antenolol

Indication: Hypertension (High Blood Pressure)

Class: Beta Blocker

• Selective: is an antagonist for only β₁

MOA: Prevents activation of β₁ receptors in:

• The heart, inhibiting increases in heart rate and contractility, reducing BP.

• The kidneys: decreases renin secretion which reduces water retention and vessel constriction, reducing BP.

Adverse Effects:

• Less likely to cause effects as it is selective, but can cause:

• Blocking β₂ receptors in the lungs prevents bronchodilation, meaning it should not be used in those with pre-existing lung condition.

• Blocking β₂ receptors in the liver and skeletal muscles prevents control of blood glucose levels. Causes vasodilation to skeletal muscles, causing cold extremities.

• Blocking β₂ receptors in the bladder prevents sphincter contraction, contributing to incontenence, loss of bladder control.

• Lipophilic beta blockers can pass the blood-brain barrier, causing sedation or feeling tired.

Pyridostigmine

Indication: Myasenthia Gravis (Damage to N_M receptors, causing skeletal muscle weakening)

Class: Peripheral Acetylcholinesterase Inhibitor

MOA: Acts as a competitive inhibitor to acetylcholinesterase, preventing binding and breakdown of acetylcholine, increasing its concentration in the synapse, enhancing neuromuscular transmission, and control of skeletal muscles.

Adverse Effects: Excess parasympathetic activation can lead to hypotension, bradycardia, increased salivation, GI upset, drowsiness, and urinary urgency.

Formoterol

Indication: Asthma and COPD

Class: β₂ agonist

• Long-Acting β₂ agonist. Is a preventer or maintenance medication, which has a a quick onset and longer lasting effects. Most of this type have a slow onset

Other: Use with inhaled corticosteroids as it dilates the airway, but doesn’t reduce inflammation. Used in combination with Ipratropium and Tiotropium in COPD.

MOA: Stimulates β₂ receptors, causing relaxing of bronchial smooth muscle, causing bronchodilation. This helps to improve airflow into and out of the lungs, assisting both asthma and COPD.

Adverse Effects:

• Tremor: activation of β₂ receptors can trigger smooth muscle contraction.

• Palpitations and Tachycardia: activation of β₂ receptors can trigger cardiac muscle contraction, increasing heart rate and contractility.

• Hyperglycaemia: activation of β₂ receptors can trigger glyconeogenesis in skeletal muscles and the liver, causing excess glucose in the blood.

Fluticasone

Indication: Asthma and COPD.

Class: Inhaled Corticosteroid

Delivery: Using a puffer, 10-60% is inhaled. This can be increased via the use of a spacer.

Other: Used after beta agonists and muscarinic antagonists in COPD.

MOA: Binds to glucocorticoid receptors and alter gene transcription in cells. They have broad anti-inflammatory and immunosuppressive effects such as decreasing number of inflammatory cells, damage to the airways, and vascular permeability/oedema.

Adverse Effects:

• Oral Thrush: yeast infection caused by immunosuppressive effects. can be avoided by rinsing out mouth.

• Dysphonia: hoarse voice due to effects on the vocal cords.

• Loss of bone density, adrenal suppression, cataracts and diabetes.

• Slightly increased risk of pneumonia.

Montelukast

Indication: Asthma, particularly NSAID exacerbated disease.

Class: Leukotriene receptor antagonist

MOA: Binds to leukotriene receptors and prevents leukotriene binding, preventing the attraction of eosinophils and effects of broncho-constriction, airway oedema, mucus hyper secretion, and eosinophil activation.

Delivery: orally via tablet.

Adverse Effects: Associated with nightmares, hallucinations or mood changes, especially in children.,

Omalizumab

Indication: Asthma (Allergenic)

Class: Anti IgE Antibodies

MOA: uses monoclonal antibodies directed against IgE, preventing binding with FC receptors on mast cells, preventing mast cell degranulation, preventing bronchoconstriction, mucus hyper secretion, and airway oedema.

Adverse Effects:

• Injection site reactions.

• Anaphylactic reactions as it interferes with the normal immune response.

Dupilumab

Indication: Asthma (used for maintenance treatment)

Class: Interleukin 4 and 13 Inhibitor

MOA: Prevent the actions of interleukin 4 and 13 activating B cells, preventing the production of IgE antibodies, and hence the recruitment of eosinophils. This prevents airway remodelling, bronchoconstriction, mucus production and airway oedema.

Adverse Effects: generally well tolerated.

Benralizumab

Indication: Asthma with high eosinophil levels which is not responding to other treatment.

Class: Anti-Interleukin 5 Therapy

MOA: Blocks interleukin 5 receptors, preventing its binding. This reduces the production and survival of eosinophils, reducing chronic inflammation, bronchoconstriction, and excess mucus production.

Adverse Effects: generally well tolerated.

Tiotropium

Indication: Asthma (prevention and maintenance treatment), COPD.

• Used only in severe asthma, as cholinergic stimulation is not a major factor in mild asthma. It is added for severe, poorly controlled asthma with frequent symptom flare ups and symptoms.

• Used when long-acting beta-2 agonists and inhaled corticosteroids have had minimal effects.

Class: Muscarinic Receptor Antagonists

• Long acting Muscarinic Receptor Antagonists.

Other: Can be taken in combination with Olodaterol (ultra long acting beta agonist)

MOA: Used to block the acetylcholine from binding to M3 receptors, preventing the effects of bronchoconstriction and mucus hypersecretion.

Adverse Effects: Blocked M3 Receptors can lead to:

• Dry mouth

• Blurred Vision

• Urinary Retention

Ipratropium

Indication: COPD

Class: Muscarinic Receptor Antagonist

• Short Acting Muscarinic Receptor Antagonist

MOA: Used to block the acetylcholine from binding to M3 receptors, preventing the effects of bronchoconstriction and mucus hypersecretion.

Adverse Effects: Blocked M3 Receptors can lead to:

• Dry mouth

• Blurred Vision

• Urinary Retention