Rx Note

Introduction Cardiovascular disease (CVD) has been the leading cause of death in Malaysia for over a decade. CVD includes coronary heart disease (CHD), cerebrovascular disease (strokes) and peripheral arterial disease (PAD). The common cardiovascular risk factors include dyslipidemia, hypertension , diabetes mellitus , smoking and overweight/obesity Commonly used cut off values for dyslipidemia are Total cholesterol (TC) > 5.2 mmol/L High density lipoprotein cholesterol (HDL-C) <1.0 mmol/L (males) or <1.2 mmol/L (females) Triglycerides (TG) >1.7 mmol/L Low density lipoprotein cholesterol (LDL-C) levels - will depend on the patient's CV risk Low-density lipoprotein cholesterol (LDL-C) is an important causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Higher lifelong exposure to LDL-C lead to acute coronary syndromes earlier in life. Measurement of Lipids A standard lipid profile includes measurement of plasma or serum TC, LDL-C, HDL-C and TG. LDL-C ...

Introduction Statins are widely recognized as the first-line lipid-modifying therapy for reducing cardiovascular risk due to consistent results of numerous randomized primary and secondary prevention clinical trials. They achieve this by inhibiting the hydroxymethylglutaryl coenzyme A reductase (HMG-CoA reductase), which catalyses the first committed step of cholesterol synthesis in the liver. Statins are hepatoselective with extensive first-pass metabolism , which is advantageous because the liver is the main site of cholesterol synthesis, with extrahepatic sites synthesising essential cholesterol. NOTE: There is growing interest in their potential pleiotropic effects , which are actions unrelated or indirectly related to their effect on plasma LDL levels, such as anti-infammatory and antioxidant effects. Administration Time When advising patients on statin use, it is commonly recommended to take statins at night. However, this statement may not apply universally to all statins av...

Introduction As I was reading about sulfonylureas on Rang and Dale's Pharmacology , I learned that sulfonylureas are classified as first-generation and second-generation agents, based on their relative potency. First-generation agents (e.g. chlorpropamide, tolazamide and tolbutamide) are lower in potency in relative to the second-generation drugs (e.g. glyburide, glipizide, and glimepiride) and are rarely used these days due to higher risk of adverse effects. To illustrate, glibenclamide is 150 times more potent than tolbutamide. One day, a second-year pharmacy student asked me on what "more potent drug" meant. I had to paused and think about how to explain potency. Maximal Effective Concentration (EC 50 ) In pharmacology, potency is a measure of drug activity expressed in terms of the amount required to produce a given intensity of effect. Maximal effective concentration (EC 50 ) is a parameter used to determine drug potency. It refers to the concentration of a drug, a...

Introduction Lipids, including cholesterol and triglycerides, are transported in the plasma as lipoproteins, of which there are 4 classes. Chylomicrons transport triglycerides and cholesterol from the gastrointestinal tract to the tissues, where triglyceride is split by lipoprotein lipase, releasing free fatty acids and glycerol which are taken up in muscle and adipose tissue. Chylomicron remnants are taken up in the liver, where cholesterol is stored, secreted in bile, oxidised to bile acids or converted into VLDLs. Very-low-density lipoproteins (VLDLs) transport cholesterol and newly synthesised triglycerides to the tissues, where triglycerides are removed as before, leaving LDLs. Intermediate-density and low-density lipoprotein (LDL) particles with a large component of cholesterol; some cholesterol is taken up by the tissue and some by the liver, by endocytosis via specific LDL receptors. High-density lipoprotein (HDL) particles absorb cholesterol derived from cell breakdown in ...

Introduction Stable ischaemic heart disease (SIHD) is caused by obstructive atherosclerotic plaque in one or more epicardial coronary arteries. Inappropriate, insufficient or untreated SIHD cannot only lead to MI and cardiac death, but also cause the development of heart failure , arrhythmias and valvular disease. Clinical Presentation Chest pain (angina) from exertion is the cardinal symptom of myocardial ischaemia in patients with SIHD. In this setting, the exertion produces an increase MVO 2 that exceeds what can be provided by the fixed decrease in myocardial oxygen supply from the obstructive atherosclerotic plaque. Typically, rest or the use of sublingual nitroglycerin relieves the symptoms. Management The treatment of patients with SIHD typically involves 2 complementary strategies. Slowing the progression of atherosclerosis and preventing complications such as MI, HF, stroke and death. It focuses on risk-factor modification and providing vasculoprotection therapies. Daily ...

Introduction Acute coronary syndrome (ACS) is an acute manifestation of coronary artery disease (CAD). Patients with ACS typically experience an acute reduction in coronary blood flow most often due to a ruptured atherosclerotic plaque and subsequent formation of an intracoronary thrombus. The reduction in coronary blood flow produces myocardial ischemia and, if left untreated, may lead to myocardial infarction (MI). Signs and Symptoms The "classic" presentation of ACS is abrupt onset of substernal chest pain often described as a sensation of squeezing, heaviness, or tightness in the chest that may radiate, typically to either or both arms or shoulders (radiation to the left side is more common), the neck or the jaw. Patients with ACS may also experience diaphoresis, nausea, vomiting and dyspnoea. As many as one-third patients may present with atypical symptoms that do not include chest pain. Epigastric pian Indigestion Stabbing Pleuritic chest pain Increasing exertional d...