Cardiovascular Drugs

As blood is pumped through the arteries, it creates pressure within the wall of the arteries As the heart contracts, this increased pressure is called the systolic pressure

As the heart relaxes and fills, this decreased pressure is called the diastolic pressure

Blood Pressure Blood pressure is written as a fraction of systolic over diastolic pressure in mmHg(mercury) Normal is 120/80 mmHg

Blood Pressure Blood pressure is VITAL to life A blood pressure of zero is a sign of death Blood pressure is a VITAL sign

Let’s take a blood pressure

Hypertension Is High Blood Pressure HTN

Hypertension Is measured by consistent elevation in blood pressure, either Systolic ≥ 140mmHg Diastolic ≥90mmHg

Hypertension Long standing, uncontrolled HTN damages blood vessels resulting in many types of organ damage

Essential Hypertension Essential HTN is the most common form of HTN Cause of essential HTN is unknown

Essential Hypertension has many risk factors: Family history of HTN Sex Race Salt Stress Obesity, lack of exercise Smoking

Secondary HTN Unlike essential HTN, secondary HTN has a specific cause for the elevated blood pressure

Secondary HTN Kidney Disease Pheochromocytoma – a type of tumor that makes too much epinephrine or too much catecholamines Cushing’s Disease Pregnancy Vascular Anomalies Neurologic Disease

Symptoms of HTN HTN usually has NO symptoms It is usually detected on a routine visit to a medical clinic

HTN usually has NO symptoms This is why it is so difficult to convince people to take medication for HTN

Symptoms of HTN HTN can cause many symptoms Headache and visual changes, especially during stress are common early symptoms

Symptoms of HTN When HTN is severe enough to cause acute visual, neurologic, or any other organ damage this is called MALIGNANT HYPERTENSION

HTN damages blood vessels Long term sustained hypertension damages blood vessels Blood vessels exposed to high blood pressures become thickened and hardened, making them less flexible

Arteriosclerosis Blood vessels exposed to high blood pressures become thickened and hardened, making them less flexible

HTN damages blood vessels Fatty deposits can form on the arteries call plaques, which cause the artery to narrow and become blocked This is called Atherosclerosis

Know the difference between: Arteriosclerosis Atherosclerosis

Infarction When narrow arteries become blocked and blood supply to an organ is stopped, organ damage results This damage is called infarction

HTN causes brain damage HTN is a major cause of stroke - brain attack - cerebrovascular accident (CVA) - cerebral infarction - apoplexy

HTN causes brain damage

Aneurysm With high blood pressure, a weakening of the arterial wall may balloon out (aneurysm) and burst causing hemorrhage (bleeding) and even death

Aneurysm

Aneurysm Although aneurysm can occur on any artery, the two most common places for aneurysm are: Brain – cerebrovascular aneurysm Aorta – abdominal aortic aneurysm

HTN damages the eyes Because HTN damages blood vessels, HTN damages the blood supply to the eyes, and can lead to blindness

Normal Retina

HTN damages the kidneys Because HTN damages the blood vessels, HTN damages the kidneys, this is called nephrosclerosis, and can lead to kidney failure

Nephron

HTN damages the heart Because HTN damages the blood vessels, HTN damages the heart by infarction, hypertrophy or cardiomyopathy

Myocardial Infarction

Ventricular Hypertrophy

Dilated Cardiomyopathy

The kidneys help regulate blood pressure The kidneys play an important role in the long-term regulation of blood pressure

Immediate Control Parasympathetic Nervous System Sympathetic Nervous System/Adrenergic NS

Long Term Control Kidneys

Kidneys and Blood Pressure Kidneys help regulate the balance of salt and water in the body Kidneys excrete water soluble waste substances, salt and water

Kidneys are Filters The kidneys contain millions of microscopic filtering units, called nephrons which are the working components of the kidneys

Kidneys are Filters Many substances cannot pass through the filter and remain in the blood Many substances pass through the filters (like glucose) but are reabsorbed back into the blood

Kidneys are Filters Many substances pass through the filters and are excreted into the urine

Kidneys regulate blood volume When blood volume decreases, kidneys will retain salt and water When blood volume increases, kidneys will excrete salt and water

Renal Hormones and Volume Control Blood volume is monitored by the kidneys and continually adjust water and salt levels to help maintain consistent blood pressure

Renal Hormones and Volume Control The blood vessels supplying the nephrons contain special cells that detect blood pressure

Renal Hormones and Volume Control If blood pressure falls below a set point, a renal hormone called Renin is secreted into the blood stream

Renin and Volume Control Renin converts angiotensin to angiotensin 1, which is converted to angiotensin 2 by the lungs Angiotensin 2 causes vasoconstriction which increases blood pressure

Angiotensin 2 also stimulates the adrenal cortex to produce aldosterone

Aldosterone and Volume Control Aldosterone acts on the kidneys to keep salt and water in the blood, resulting in increased blood volume

Medulla – inside - epinephrine (adrenaline) Cortex – outside - aldosterone (mineralocorticoid) - hydrocortisone (glucocorticoid)

Antidiuretic Hormone (ADH) and Volume Control Antidiuretic Hormone (ADH) is also called Vasopressin, secreted by the brain in response to low blood pressure, acts on the kidneys to retain water, resulting in increased blood volume

Drugs for HTN Adrenergic Antagonists - β-blockers - “Beta Blockers” Propanolol Atenolol

Adrenergic Antagonists - α-blockers - alpha-blockers Doxazosin

Drugs for HTN Central α-agonist - clonidine

Clonidine stimulates alpha adrenoreceptors in the brain stem Clonidine stimulates alpha adrenoreceptors in the brain stem. This action results in reduced sympathetic outflow from the central nervous system and in decreased in peripheral resistance, renal vascular resistance, heart rate and blood pressure

Drugs for HTN Thiazide diuretic Hydrochlorothiazide (HCTZ)

Drugs for HTN Angiotensin Converting Enzyme Inhibitors ACE Captopril

Drugs for HTN Angiotensin II receptor blockers - losartan

Drugs for HTN Calcium Channel Blockers - dilates arterioles - relaxes smooth muscle - come in 3 classes

Drugs for HTN Calcium channel blockers - nifedipine is a dihydropyridine CCB

Drugs for HTN Calcium Channel Blocker - Verapamil is a phenylalkylamine ccb

Drugs for HTN Calcium Channel Blocker - Diltiazem is a benzothiazepine ccb