Rx Note

Introduction Pharmacogenomics is the science which examines inherited variations in genes that determine a patient's response to a drug. Beyond tailoring a drug to an individual based on size, weight or age, the science of pharmacogenomics strives to tailor drug therapy to individual patients based on their own unique molecular characteristics (e.g. individual differences in drug-metabolizing enzymes, drug transporter activity, receptor sensitivity). Moreover, pharmacogenomic testing can help identify patients at higher risk of serious adverse drug reactions or therapeutic failure, and sometimes it can explain unexpected adverse effects or poor efficacy in patients already on drug therapy. Genetic Variation Major genetic variation is found in the cytochrome CYP450 group of isoenzymes. This can result in either inadequate responses to drugs or increased risk of ADRs . Clinically relevant genetic variation has been seen in CYP2D6, CYP2C9, CYP2C19 and CYP3A5. Examples Abacavir hyper...

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...

Introduction Platelets maintain the integrity of the circulation. When platelets are activated, they undergo a series of reactions that are essential for haemostasis, important for healing of damaged blood vessels. Aspirin Low-dose aspirin in chronic use profoundly (>95%) inhibits platelet TXA 2 synthesis by irreversible acetylation of a serine residue in the active site of cyclo-oxygenase I (COX-1). Owing to association with Reye's syndrome , manufacturer advises aspirin-containing preparations should not be given to children under 16 years, unless specifically indicated , e.g. for Kawasaki disease . Contraindications to aspirin include a hypersensitivity to aspirin and major GI intolerance. Dipyridamole Dipyridamole inhibits platelet aggregation by several mechanisms, including Inhibition of phosphodiesterase, Block of adenosine uptake into red cells and Inhibition of TXA2 synthesis It is used in addition aspirin in some patients with stroke or transient ischaemic attack. T...