P13

Question 1

Paclitaxal

Answer 1

Microtubule stabilisation agent

MoA:

• Paclitaxel binds to the β subunit of tubulin causing hyper-stabilisation of the microtubule.
• This prevents the cell from undergoing disassembly and therefore reorganising the microtubule cytoskeleton. This adversely affects cell function, as a dynamic microtubule network is key to effective cellular transport.

Use:

• Paclitaxel is a taxoid antineoplastic agent
• Used for advanced ovarian carcinoma + breast cancer

Question 2

Cisplatin

Answer 2

Antineoplastic alkylating agent

Use:

• Alkylating agent
• Cancer treatment

Question 3

Isoniazid

Answer 3

Bactericidal agent

MoA:

• Isoniazid is a prodrug and must be activated by bacterial catalase.
• Once activated, isoniazid inhibits the synthesis of mycolic acids, an essential component of the bacterial cell wall. Isoniazid also disrupts DNA, lipid, carbohydrate, and nicotinamide adenine dinucleotide (NAD) synthesis and/or metabolism

Use:
- Isoniazid is a highly specific bactericidal agent, which targets mycobacterium and is ineffective against other microorganisms

Question 4

Ethambutol

Answer 4

Bactericidal agent

MoA:
- Not fully understood but it is thought to inhibit arabinosyl transferases which is involved in cell wall biosynthesis.

Use:

• Ethambutol is an oral chemotherapeutic agent
• Apecifically effective against actively growing mycobacterium

Question 5

Rifampicin

Answer 5

Broad spectrum bactericidal

MoA:

• Inhibition of DNA-dependent RNA polymerase, leading to a suppression of RNA synthesis and cell death.
• Importantly Rifampicin can target bacterial but not mammalian versions of the enzyme.

Use:

• Rifampicin is a broad spectrum antibiotic (targets both gram-positive and gram-negative organisms), which is easily absorbed and distributed within the body
• Due to the emergence of resistant bacteria, the use of Rifampicin is restricted to mainly mycobacterial infections

Question 6

Pyrazinamide

Answer 6

Antibiotic

Use:

• Pyrazinamide a highly specific agent used with other drugs to treat TB
• It is active only against Mycobacterium tuberculosis and is active only at a slightly acid pH

Question 7

Ciprofloxacin

Answer 7

Broad spectrum antibiotic (quinolone)

MoA:
- Inhibition of topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, strand supercoiling repair, and recombination

Use:
- Ciprofloxacin can be used against a wide range of gram-negative and gram-positive microorganisms

Question 8

Salmeterol

Salbutamol

Answer 8

Beta 2 adrenergic agonist use

Use:

• B2-receptor stimulation in the lung causes relaxation of bronchial smooth muscle, bronchodilation, and increased bronchial airflow.
• They are used to manage asthma and other chronic obstructive airway diseases

Question 9

Budesonide

Answer 9

Anti-inflammatory corticosteroid

Use:

• Crohn’s disease
• Asthma inflammation
• UC

MoA:

• Has a high glucocorticoid effect and a weak mineralocorticoid effect.
• Its binding affinity to the glucocorticoid receptor is higher than cortisol and prednisolone

Question 10

Montelukast

Answer 10

Leukotriene receptor antagonist

Use:
- Used as an alternative to anti-inflammatory medications in the management of asthma and exercise-induced bronchospasm (EIB)

Question 11

Ipratropium

Answer 11

Anticholinergic agent

Use:

• Bronchodilator used in the management of cholinergic-mediated bronchospasm associated with COPD
• Treatment of rhinorrhoea associated with the common cold or with allergic or non-allergic seasonal rhinitis.

Question 12

Verapamil

Answer 12

Class IV anti-arrhythmia agent

MoA:
- Verapamil inhibits voltage-dependent calcium channels. In the heart it blocks the L-type calcium channels causing a reduction in ionotropy and chronotropy, reducing heart rate and blood pressure.

Question 13

Diltiazem

Answer 13

Calcium channel inhibitor

Use:
- Used alone or with an ACE inhibitor, to treat hypertension, chronic stable angina pectoris, and Prinzmetal’s variant angina

Question 14

Atenolol

Answer 14

Atenolol has similar properties to propranolol and it is a β1-selective antagonist

MoA:
- Higher doses of Atenolol also competitively block β2-adrenergic responses in the bronchial (in asthmatic patients can cause bronchoconstriction) and vascular smooth muscles

Question 15

Atropine

Answer 15

Antimuscarinic agent

MoA:
- Atropine binds to and inhibits the muscarinic (M2) acetylcholine receptor.

Use:
- Prevents or abolishes bradycardia, asystole and cardiac arrest

Question 16

Glyceryl trinitrate

Answer 16

Vasodilator

Use:
- Treatment of angina pectoris and perioperative hypertension, to produce controlled hypotension

Question 17

Amiodarone

Answer 17

Antianginal and antirhythmic agent

Amiodarone is a Vaughan-Williams Class III antiarrhythmic agent

Question 18

Adenosine

Answer 18

Adenosine is an endogenous nucleoside.

MoA + Use:

• Slow conduction time through the AV node and so interrupt the re-entry pathways through the AV node, resulting in the restoration of normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT), including PSVT associated with Wolff-Parkinson-White Syndrome
• Increase blood flow in normal coronary arteries with little or no increase in stenotic arteries

Question 19

Lidocaine

Answer 19

Anaesthetic agent + Class Ib antiarrthmatic drug that blocks voltage-sensitive sodium channels during phase 0 of the cardiac action potential, thus slowing and depressing impulse conduction

Use:

• Treat ventricular tachyarrhythmias associated with MI.
• Lidocaine depresses Ventricular excitability and increases the stimulation threshold of the ventricle during diastole.
• The sinoatrial node is, however, unaffected.