Cardiovascular System Lecture 4 PDF

Cardiovascular System  Phytomedicines and Cardiovascular diseases Phytomedicines play a significant role in the treatment of mild forms of heart failure and coronary insufficiency, in the prevention and treatment of atherosclerosis and its sequelae, and in the symptomatic tre...

Cardiovascular System  Phytomedicines and Cardiovascular diseases Phytomedicines play a significant role in the treatment of mild forms of heart failure and coronary insufficiency, in the prevention and treatment of atherosclerosis and its sequelae, and in the symptomatic treatment of chronic venous insufficiency. The pharmacologic therapy of heart failure is based on three principles: Increasing the efficiency of the heart muscle (cardiac glycosides), Reducing the preload (diuretics), Reducing the afterload (vasodilators, ACE inhibitors). But cardiac glycosides and other positive inotropic agents ( also shorten the refractory period, thereby increasing the risk of cardiac arrhythmias  THE STORY OF FOXGLOVES A old woman in Shrospshire (England) used to prescribe a secret cure for the treatment of dropsy and other cardiac diseases. This secret recipe was found to contain foxgloves (Digitalis purpurea). William Withering, the English physician and botanist after getting the hint from the old lady, used the herb and observed that foxglove has a power over the motion of the heart, to a degree yet unobserved in only other medicine. Powdered foxgloves, and its active constituents Digoxin and, Digitoxin, are now among the most widely prescribed medicines for heart patients.  O O R CH3 Digitoxin: R = H CH3 H Digoxin: R = OH CH3 H OH O O CH3 H O O CH3 OH O O OH HO OH  There are only a few herbs, however, for which safety and efficacy have been adequately proven: Hawthorn (heart failure and coronary insufficiency) Garlic (atherosclerosis), Ginkgo extract (arterial occlusive disease), Horse chestnut extract (chronic venous insufficiency). Herbal remedies for angina pectoris, cardiac arrhythmias, and hypertension and hypotension.  Heart Failure and Coronary Insufficiency The classic remedies used to treat myocardial insufficiency are the cardiac glycosides derived from purple and Grecian foxglove (Digitalis species). These compounds are colorless, bitter- tasting substances that cause local irritation. Their chemical compositions are known, and they can be synthetically produced, but for economic reasons the 14 pure glycosides or their precursors are still obtained by extraction from digitalis leaf.  Because the cardiac glycosides are specific, identifiable chemical compounds that have a narrow therapeutic dose range, they are not considered phytotherapeutic agents and are outside the realm of herbal medicine. Galenic preparations made from digitalis leaves are obsolete in modern pharmacotherapy. Details on the pure glycosides and their actions can be found in textbooks of pharmacology.  Hawthorn ‫الزعرور‬ Hawthorn (Crataegus species) has been used to treat heart disease as far back as the 1st century. By the early 1800s, American doctors were using it to treat circulatory disorders and respiratory illnesses. Traditionally, the berries were used to treat heart problems ranging from irregular heartbeat, high blood pressure, chest pain, hardening of the arteries, and heart failure. Today, the leaves and flowers are used medicinally. There is even research to suggest that hawthorn might be effective when used in the treatment of mild-to-moderate heart failure.  Hawthorn Animal and laboratory studies report hawthorn contains antioxidants, including oligomeric procyandins (OPCs, also found in grapes) and quercetin. Antioxidants are substances that destroy free radicals, which are compounds in the body that damage cell membranes, tamper with DNA, and even cause cell death. Free radicals occur naturally in the body and grow in number as we age. Environmental toxins (including ultraviolet light, radiation, smoking, some medicines, and air pollution) can also increase the number of these damaging particles. Scientists believe free radicals contribute to the aging process (such as wrinkling), as well as the development of a number of health problems, including cancer and heart disease. Antioxidants in hawthorn may help stop some of the damage from free radicals, especially when it comes to heart disease.  Flowering branch of hawthorn (Crataegus species). Hawthorn is a member of the Rosaceae family, but the unpleasant aroma of its blossoms attracts only flies. The tall shrubs are distributed throughout Europe  What is it Made Of? Hawthorn contains many substances that may benefit the heart. These antioxidant flavonoids, including oligomeric procyandins (OPCs, also found in grapes) , may help dilate blood vessels, improve blood flow, and protect blood vessels from damage. The berries, leaves, and flowers of the hawthorn plant have been used for medicinal purposes. Most modern preparations use the leaves and flowers, which are believed to contain more flavonoids than the berries.  Medicinal Uses and Indications Hawthorn is used to help protect against heart disease and help control high blood pressure and high cholesterol. Both animal and human studies suggest hawthorn increases coronary artery blood flow, improves circulation, and lowers blood pressure. It has also been used on the skin to treat boils and skin sores. Heart failure Hawthorn has been studied in people with heart failure (a condition in which the heart is unable to pump enough blood to other organs in the body).  The updated 1994 Commission E monograph on hawthorn leaves and flowers states that the extract is indicated for "declining cardiac performance consistent with stage II failure according to NYHA criteria." The recommended dosage is 160-900 mg/day of the crude water-and-alcohol extract with a designated content of flavonoids (4-20 mg) or oligomeric procyanidins (30-160 mg). Hawthorn preparations should be taken orally and should be continued for at least 6 weeks. Side effects of Hawthorn are rare, but may include headache, nausea, and palpitations (a feeling of a racing heart).  Possible Interactions Digoxin: Hawthorn may enhance the activity of digoxin, a medication used for irregular heart rhythms. Beta-blockers: These drugs are used to treat heart disease by lowering blood pressure and dilating blood vessels. Hawthorn can make the effects of these drugs stronger. They include: Atenolol (Tenormin) Metoprolol (Lopressor, Toprol-XL) Propranolol (Inderal, Inderal LA) Calcium channel blockers (CCBs): These drugs are used to treat high blood pressure and angina by dilating blood vessels. Hawthorn can make the effects of these drugs stronger. They include: Norvasc (amlodipine) Cardizem (diltiazem) Procardia (nifedipine)  Possible Interactions Phenylephrine: In a laboratory study, an alcoholic extract of hawthorn fruit reduced the effects of phenylephrine, a medication that constricts blood vessels and is commonly found in nasal decongestant products. Medications for male sexual dysfunction (Phosphodiesterase-5 inhibitors): When used together with Hawthorn, it may result in blood pressure dropping too low. Nitrates: These medications increase blood flow to the heart and taking Hawthorn together with them might increase the chance of dizziness or light headedness.  Garlic (atherosclerosis), Overview Garlic has been used as both food and medicine for thousands of years, dating back to when the Egyptian pyramids were built. In early 18th century France, gravediggers drank crushed garlic in wine believing it would protect them from the plague ‫الطاعون‬. During both World War I and II, soldiers were given garlic to prevent gangrene. It was also used as an antiseptic and applied to wounds to prevent infection.  Garlic (atherosclerosis) Overview Today garlic is used to help prevent heart disease, including atherosclerosis or hardening of the arteries (plaque buildup in the arteries that can block the flow of blood and may lead to heart attack or stroke), high cholesterol, high blood pressure, and to boost the immune system. Eating garlic regularly may also help protect against cancer.  Garlic Claims: Antibiotic, antiviral, general cure all, lowering of blood pressure, cholesterol, and regulation of circulatory system. Garlic Used in Europe as an approved remedy for cardiovascular conditions and for the use of the flu and colds.  The conditions for which garlic is showing the most promise include the Heart disease following: Garlic is most often mentioned as an herb for heart disease and atherosclerosis (hardening of the arteries). But evidence is mixed. Some studies suggest that garlic may help prevent heart disease. It may slow down atherosclerosis and lower blood pressure a little, between 5% and 8%. Most of the studies on high blood pressure use a specific formulation called Kwai. One study that lasted 4 years found that people who took 900 mg daily of standardized garlic powder slowed the development of atherosclerosis. Garlic also seems to act as a blood thinner, which may help prevent heart attacks and strokes.  The conditions for which garlic is showing the most promise include the following: Cancer Garlic may strengthen the immune system, helping the body fight diseases such as cancer. In test tubes, garlic seems to kill cancer cells. population studies, ones that follow groups of people over time, suggest that people who eat more raw or cooked garlic are less likely to get colon and stomach cancers and cancer of the esophagus. In fact, researchers who reviewed 7 studies found a 30% reduction in risk of colorectal cancer among people who ate a lot of raw or cooked garlic. Garlic supplements do not seem to have the same effect.  Horse chestnut extract Aesculus hippocastanum Also known as buckeye and Spanish chestnut, the seeds, leaves, bark and flowers of horse chestnut trees have long been used medicinally. The trees are native to Eastern Europe but can be found throughout the Northern Hemisphere. Horse chestnut extract Though it is sometimes referred to as buckeye, it is not the same species as that of buckeye trees that grow in Ohio and California.  Be careful not to confuse aesculus hippocastanum (Horse chestnut) with aesculus californica (California buckeye) or aesculus glabra (Ohio buckeye). Some people call any of these plants horse chestnut. This information applies to aesculus hippocastanum.  Medicinal uses Horse chestnut seed extract has been extensively studied for chronic venous insufficiency (CVI), a circulation problem in which the veins do not efficiently return blood from the legs to the heart. This condition is associated with varicose veins, pain, ankle swelling, itching, and nighttime leg cramping. A review of all the clinical trials concluded that the evidence suggests that horse chestnut seed extract is an efficacious and safe short-term treatment for CVI. One study actually found it as effective as compression stockings.  Dose Horse chestnut seed extract is also used to treat hemorrhoids. One small study showed that horse chestnut extract providing 120 mg of horse chestnut seed extract per day significantly improved symptoms of pain, itching, burning, and swelling. Available in: Extracts standardized to contain 16 to 20 percent aescin.  How does it work? Horse chestnut contains a substance that thins the blood. It also makes it harder for fluid to leak out of veins and capillaries and weakly promotes fluid loss through the urine to help prevent water retention (edema).  Herb / drug interactions: Horse chestnut extract might slow blood clotting, increasing the risk of bruising and bleeding in people taking aspirin, ibuprofen, coumadin or other drugs that slow clotting. Horse chestnut may slow the process by which the body eliminates lithium, a drug used to treat the manic side of bipolar disorder. This effect could lead to serious side effects. Horse chestnut may lower blood sugar, which could amplify the effects of drugs that lower blood sugar in people with diabetes.