Pharmacology

Introduction Statins have revolutionised the management of hypercholesterolaemia. Statins have become essential in the management of patients with, or at risk, of cardiovascular disease including coronary artery disease (CAD), cerebrovascular disease and peripheral vascular disease (PVD). Indications Statins were primarily created to treat hypercholesterolaemia, which is an independent risk factor for cardiovascular disease. Statins are indicated in both primary and secondary prevention of cardiovascular disease for many conditions. Primary prevention Cardiovascular risk assessment score ≥10%* and ≤ 84 years old (risk/benefit if >84) Cardiovascular risk assessment score ≥10%* and type 2 diabetes mellitus (T2DM) Type 1 diabetes mellitus (T1DM) and additional criteria (age, kidney disease, duration) Chronic kidney disease (CKD)

Overview Oxygen should be regarded as a drug that is prescribed for patients with hypoxaemia (low blood oxygen concentration). Oxygen is the most commonly used drug in emergency situations. It can be a life-saving drug to prevent severe hypoxaemia that refers to a low arterial oxygen concentration. However, used inappropriately oxygen can have serious or fatal consequences. The headline point is that oxygen should be used to treat hypoxaemia and maintain a patients’ saturations in the target range. This should be 94-98% or 88-92% in patients at risk of type 2 respiratory failure. When prescribing and administering oxygen there are several

Summary Metformin is considered the first-line hypoglycaemic agent for the treatment of type 2 diabetes mellitus. Metformin has been one of most prescribed medications worldwide over the last decade. The typical starting dose for adults is 500 mg daily, which can be increased to a maximum dose of 2 g daily. The most common adverse-effect is gastrointestinal upset (i.e. nausea, abdominal pain, diarrhoea), although rarely metformin can result in lactic acidosis. Origin Derived from galegine, which is a natural protein found in the plant Galega officinalis. Metformin was first synthesised around the 1920s and then used clinically in the 1950s. It is now

Introduction Airway resistance occurs as frictional forces oppose the flow of air through the conducting airways. Normal flow is laminar, the flow is ordered and quicker in the centre. As airways divide and become narrow increasingly turbulent flow occurs. Poiseuille’s equation describes resistance (if flow is laminar) with resistance (R), length (L), radius (r) and viscosity (η). π and 8 are constants: Resistance (R) = 8 x L x η / π x r4 Bronchomotor tone Bronchomotor tone controls the ease with which air is conducted through airways. It exhibits a circadian rhythm where tone is greatest in the early morning. We note from the

Overview The anti-hypertensives are an important & broad group of medications. Hypertension is a very common condition that represents a significant source of morbidity and mortality. It is a major risk factor for MI, stroke and chronic kidney disease. Hypertension is managed in a step-wise fashion according to the NICE guidelines (see our Hypertension notes for more). Several groups of drugs, by varying mechanisms, are used to reduce blood pressure. Regulation Blood pressure is maintained by a number of physiological reflexes that respond to acute and chronic changes. Blood pressure = cardiac output x peripheral vascular resistance Numerous interconnected systems contribute to the regulation of blood pressure.

Vaughan-William’s classification Anti-arrhythmics are drugs that modify cardiac conduction, they are used to treat arrhythmias and are classified according to the Vaughan-William’s system. This classification divides these drugs into four classes according to their effects on cardiac action potential. Anti-arrhythmics have complex actions and classes may overlap. It is important to note, that this classification system has become increasingly inadequate with improved understandings of drug mechanisms and development of new antiarrhythmics. Arrhythmogenesis To understand the action of the antiarrhythmics it helps to understand how arrhythmias may develop. Arrhythmias are disorders of rate and rhythm of the heart, which arise due to either abnormal generation or