CLINICAL PHARMACOLOGY

Question 1

What drugs cause Steven Johnson Syndrome?

Answer 1

1. Carbamazepine-used in treatment of epilepsy and partial seizures (Remains FIRST LINE medication)
2. Lamotrigine
3. Allopurinol
4. Sulfonamide

Question 2

What is the mechanism of action in Digoxin and what is it used for?

Answer 2

Digoxin is a cardiac glycoside that increases the force of myocardial contraction and reduces conductivity within the atrioventricular (AV) node.
It is a common agent used to manage atrial fibrillation and the symptoms of heart failure
In adults with heart failure, when it is clinically possible, digoxin should be administered in conjunction with a diuretic and an angiotensin-converting enzyme (ACE) inhibitor

Digoxin is a positive inotropic and negative chronotropic drug7, meaning that it increases the force of the heartbeat and decreases the heart rate

The inhibition of the sodium pump by digoxin increases intracellular sodium and increases the calcium level in the myocardial cells, causing an increased contractile force of the heart. This improves the left ventricular ejection fraction (EF)

Digoxin also stimulates the parasympathetic nervous system via the vagus nerve leading to sinoatrial (SA) and atrioventricular (AV) node effects, decreasing the heart rate

Question 3

Describe the mechanism of action of Nicorandil and what it is used for?

Answer 3

Nicorandil is a vasodilatory drug that functions through potassium channels and intracellular cGMP concentrations commonly used to treat angina
Nicorandil is a potassium channel opener with nitrovasodilator (NO donor) actions, making it both an arterial and a venous dilator. It causes sustained dilation of both the arterial resistance and conductive vessels that increases coronary blood flow

Question 4

What is Diltiazem mechanism of action and what is it used for?

Answer 4

Calcium-channel blockers (less correctly called ‘calcium-antagonists’) interfere with the inward displacement of calcium ions through the slow channels of active cell membranes. They influence the myocardial cells, the cells within the specialised conducting system of the heart, and the cells of vascular smooth muscle. Thus, myocardial contractility may be reduced, the formation and propagation of electrical impulses within the heart may be depressed, and coronary or systemic vascular tone may be diminished

It is used in many clinical scenarios as an antihypertensive, anti-arrhythmic, and anti-anginal.

** Primarily, diltiazem inhibits the inflow of calcium ions into the cardiac muscle during depolarization. Reduced intracellular calcium concentrations increase smooth muscle relaxation, resulting in arterial vasodilation and decreased blood pressure. **

Question 5

What is the interaction between Simvastatin and Erythromycin/Clarithromycin?

Answer 5

clarithromycin increases systemic exposure to simvastatin, leading to an increased risk of myopathy.

Question 6

What is the MOA of Ondansetron?

Answer 6

Helps treat Nausea
* 5-HT3 antagonist. Ondansetron works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.
* acts as an antagonist at the 5-HT3 receptors located in the central nervous system and peripheral system. These **receptors are found in high concentrations both on vagal nerve terminals and within the area postrema of the brain, which has been dubbed the ‘chemoreceptor trigger zone’ for emesis (vomiting). By blocking these receptors, ondansetron can prevent nausea and vomiting **triggered by chemotherapy drugs, radiation therapy, or postoperative complications.

Question 6

What is the MOA of Risperidone?

Answer 6

Risperidone is a medication that works in the brain to treat schizophrenia. It is also known as a second-generation antipsychotic (SGA) or atypical antipsychotic
The **primary action of risperidone is to decrease dopaminergic and serotonergic pathway activity **in the brain, therefore decreasing symptoms of schizophrenia and mood disorders.
5-HT2 Antagonist:

Question 7

What 2 conditions is Clopidogrel the antiplatelet of choice?

Answer 7

• peripheral arterial disease
• following an ischaemic stroke.

Question 8

Describe a side effect for Amitriptyline and why?

Answer 8

Amitriptyline: used for chronic pain (neuropathic)
Anticholinergic- hence side effect is CONSTIPATION

Question 9

Name Osmotic Laxatives and Stimulant Laxatives?

Answer 9

Osmotic: Lactulose and Macrogol
Stimulant: Senna and Bisacodyl

Question 10

What drug is given for maintenance therapy in alcohol abstinence in the community?

Answer 10

Acamprosate