Thursday, January 30, 2020
Use of Ace Inhibitors for Treatment of Hypertension Essay Example for Free
Use of Ace Inhibitors for Treatment of Hypertension Essay The prevalence of hypertension globally has sparked much research on medications and ways to cure it. Although there are varieties of medications available in the market to control hypertension, there are still none that can actually cure it. Until the time a drug to cure hypertension emerges, hypertension will be controlled by the use of antihypertensive drugs. Among the few well known classes of antihypertensive drugs is a group of angiotensin converting enzyme inhibitors or ACE inhibitors. ACE inhibitors are a fairly recent addition to the antihypertensive drug class and have been widely used since then due to its many potential benefits. ACE inhibitors are indicated for many conditions which include hypertension, prevention and treatment of cardiovascular disorders, and prevention of nephropathy in diabetes mellitus. When used in hypertension, it is done so in combination with diuretics with fairly good results. (Merck, 2003)      The use of ACE inhibitors is especially useful for congestive heart failure patients. Therefore, it is indicated in cases where hypertension exists in correlation with congestive heart failure. There has been a significant decrease in the overall morbidity and mortality rates of patients suffering from both the conditions when using ACE inhibitors.        The mode of action of these drugs is many fold, and for that reason very effective in the treatment of hypertension. For instance, it acts on the vascular system to reduce vascular pressure, which allows for less arterial pressure, combined with more venous capacity, thus immediately reducing the blood pressure. Alongside, it increases cardiac output and cardiac index and stroke volume. The main function of the ACE inhibitors, however, is the inhibition of the ACE enzyme, which is responsible for increased vascular pressure, ventricular remodeling, production of aldosterone and vasopressin respectively. (Katzung, 2004)      Such drugs however, require careful dosage regimes based on extensive studying of the case, as there are many side effects associated with these drugs. The most common of these include hypotension, due to the vasodilator effect of the drugs.(Merck, 2003)  The second most common problem is the development of persistent cough in such patients, which leads to reduction in patient compliance. The bid and tid dosage regimes also reduce the patients’ compliance. Due to its renal effects, ACE inhibitors must be used carefully in cases where damage to the kidney is expected or the kidneys are functionally impaired. For example, in patients with renal artery stenosis, the use of these drugs can lead to renal impairment. The prevention of release of aldosterone caused by these drugs impairs excretion of potassium in the body, which can lead to hyperkalemia. Increased levels can also lead to the development of angioedema, which can be life threatening. ACE inhibitors are also contraindicated in patients who are pregnant as it is teratogenic in nature. (Kaplan and Rose, 2007)     Due to the mode of activity of these drugs, the ACE inhibitors become contraindicated in cases of history of angioedemas or renal artery stenosis, compromised renal functioning capacities, aortic valve stenosis and in patients suffering from hypovolumia. (Klabunde, 2007)      Many drugs now belong to this category, however, the paper will discuss three of these, captopril, enalapril and lisinopril.       Captopril main mode of action lies in the suppression of the renin-angiotensin-aldosterone system. By inhibiting the ACE inhibitor, angiotensin I is prevented from converting into angiotensin II. Captopril enjoys universal attention due to the fact that it is the first ACE inhibitor introduced. Its mode of action and its effect were considered a breakthrough at the time of its conception. Its action is two fold. Firstly, it helps in dilating the vessels, thereby helping reduce blood pressure. Secondly, it has shown very good performance in the cases of myocardial infarction and congestive heart failure. And thirdly, it has shown good results in the prevention of diabetic nephropathy. (www.rxlist.com)     There is very little difference in the working of all the ACE drugs, however, captopril differs in this respect due to its shorter duration of action and increased chances of adverse effects.  This intensity of side effects potentiated further research, the result of which was the introduction of enalapril in the market, and still further drugs subsequently. Regardless of the drug, the ACE inhibitors generally take several weeks of administration to give full effectiveness and results. When used with thiazide diuretics, the results achieved are even more.(Merck, 2003)     Captopril is administered one hour before meals to achieve maximum peak volume concentration, which is reached within an hour of ingestion of drug. Initial dosage may be as low as 25 mg bid or tid, and gradually can be increased to double dose bid or tid. The addition of thiazide diuretics is usually carried out when using captopril alone at 50 mg alone does not sufficiently control blood pressure.(Katzung, 2004) This range can be increased to 150 mg per day, provided the use of a thiazide diuretic is also carried out. The administration of drug results in the lowering of blood pressure within one hour. Renal blood flow is increased; however, the GFR remains unchanged. When used with digitalis, captopril shows good efficacy in the treatment of congestive heart failure. Its use has been very favorable in patients who had previously suffered from myocardial infarction, or those with left ventricular dysfunction. In case of LVD and CHF or MI, the usual starting dose is 50 mg target dose. (Kaplan and Rose, 2007)     Captopril has shown to increase the risk of developing neutropenia and agranulocytosis and therefore, full blood picture is mandatory for patients using captopril for a prolonged period. Also, since mode of elimination from the body is through the kidneys, the use of captopril becomes contraindicated or at least under observation in cases of renal impairment or dysfunction. (Katzung, 2004)      Enalapril is the second drug introduced in the ACE inhibitor series. The main reason for its production was to eliminate the problems seen with the use of captopril. As in captopril, the drug utilizes the renin-angiotensin-aldosterone system. Production of enalapril involved changing the molecular constitution of captopril, and therefore, the final result was the first dicarboxylate- containing ACE inhibitor, or enalaprilat. However, this modification limited the use of this drug as intravenous injection only. Further modifications in this structure led to the oral form by the name enalapril. (www.rxlist.com)     Enalapril works by converting itself through hydrolysis into enalaprilat in the body. Enalaprilat then inhibits the ACE enzyme. The peak serum levels are reached within an hour of administration of the drug. As opposed to captopril, enalapril absorption is independent of gastric contents; rather it is dependant on the urinary recovery. In hypertensive patients, the dosage of enalapril results in both supine and standing but not orthostatic hypotension. This effect is not seen in case of captopril. The antihypertensive activity becomes visible within one hour of administration of the drug. This effect then remains for around 24 hours. Similar to captopril, enalapril shows improved hypertensive control when administered with a thiazide diuretic. it is also indicated for cases suffering from heart failure, and asymptomatic left ventricular dysfunction. (Kaplan and Rose, 2007)      Unlike captopril, which can be administered simultaneously with a preceding diuretic, enalapril can only be started after cessation of the diuretic after two to three days. This is essential to minimize the risk of developing hypotension. If this is not possible a test dose of 2.5 mg is given for at least two hours under observation, and the drug administered accordingly. The usual dosage regime may vary from 10 to 40 mg per day, and that is if the patient is not on a diuretic. Dose adjustment becomes necessary for patients who have impaired renal function, which may require reduction of the dose to almost half of the average 5 mg. this dosage is amenable to changes based on the blood pressure response seen. (www.rxlist.com)      Enalapril is highly favored over captopril as it has lesser side effects than its predecessor. It has a well toleration response, and the adverse effects are very mild in nature. Patients may complain of fatigue, asthenia, diarrhea and nausea, headache and dizziness, cough and skin rash. These symptoms can be present with varying degrees according to the reason why the drug is being administered. For example in heart cases, it can also lead to syncope symptoms and some differences in the special sensory perceptions. Angioedema is perhaps the most serious side effect of enalapril, with severity seen more in blacks than in non-black populations. This can be very fatal should laryngeal angioedema ensue. Initial doses can lead to fall of blood pressure and hypotension, which must be monitored very closely. Hyperkalemia, increase in blood urea nitrogen and serum creatinin levels, and decrease in hematocrit and hemoglobin can also be seen. Liver enzymes can also become elevated. (Merck manual, 2003)      The effects of enalapril were much improved and effective with lesser side effects when compared to captopril, however, the speed of effect was still high in the case of captopril. The third drug to get introduced in the series of ACE inhibitors became lisinopril. The drug was important as it was the first hydrophilic ACE inhibitor introduces, with longer half life and penetration in the tissue. The drug remains the same even after excretion from the body, and is indicated for all the conditions mentioned above for which ACE inhibitors are introduced. While captopril and enalapril were made for bid and tid dosages, lisinopril, due to its longer half life, is generally administered once a day, helping aid patient compliance.      The mode of action is similar to its sister drugs, that is the drug acts by inhibiting the ACE enzyme. The peak serum concentration of this drug however, is reached after 7 hours, compared to one hour of both captopril and enalapril. When used for hypertension, it results in the reduction of both standing and supine hypertension, with â€Å"no compensatory tachycardia†(Rx list, 2007)      The dosage of lisinopril is given according to the drug history of the patient. Patients with no use of diuretics are given 10 mg per day as initial dose. This can be increased from 20 to 40 mg as the case may need. In diuretic using patients, the protocol for the administration of lisinopril is the same as for enalapril. The diuretic is stopped two to three days prior to the administration of lisinopril, and observed for signs of hypotension. Dosage is then adjusted according to the body response of the patient. This drug should not be given along with any potassium supplements as it can lead to hyperkalemia. Renal status similarly, addresses the dosage of the drug, with 10 mg as standard for normal kidney function, 5 mg for moderate to severe renal impairment, and 2.5 mg or so for dialysis patients after proper observation and blood pressure response. (Klabubde, 2007)     Side effects of lisinopril are not so different from the side effects seen in the case of enalapril and captopril. However, cough becomes the primary side effect of this drug along with fatigue and asthenia etc. In all cases of ACE inhibitors, the side effects must be monitored closely and managed accordingly should the need arise. (ACE Inhibitors, 2004)       In conclusion, the introduction of ACE inhibitors has been a welcome addition in the antihypertensive drug family and is now used widely due to its excellent prognosis in patients with concurrent heart conditions. Its use with thiazide diuretics has been widely documented and further studies will help in the introduction of much improved brands of ACE inhibitors. References ACE inhibitor drugs. Site last accessed on August 5, 2007 from www.rxlist.com ACE inhibitors, 2004. Site last accessed on August 5, 2007 from http://www.chfpatients.com/ace_old.htm Norman A Kaplan and Burton D Rose, 2007. ACE inhibitors in the Treatment of Hypertension. Site last accessed on August 5, 2007 from http://patients.uptodate.com/topic.asp?file=hyperten/10107#1 Richard E. Klabunde, 2007. Angiotensin Converting Enzyme Inhibitors. Site last accessed on August 5, 2007 from http://cvpharmacology.com/vasodilator/ACE.htm Bertram G. Katzung, 2004. Basic and Clinical Pharmacology, ninth edition. The Merck Manual of Medical Information. Second Home Edition. Section III, Heart and Blood Vessel Disorders.
Tuesday, January 21, 2020
Mystery Surrounding the Phoenix Lights: Evidence of UFO Sighting? :: Expository Essays Research Papers
Mystery Surrounding the Phoenix Lights: Evidence of UFO Sighting? Abstract  The events that occurred in Phoenix on March 13, 1997 still have the world at a loss. A triangle (boomerang) shaped craft with seven lights on the main body and one trailing behind the rest appeared over Phoenix. Some believe that they were just flares used by the military, but others think that it was definitely extraterrestrial. Much evidence has been found, but the mystery remains.  On March 13, 1997, an inexplicable phenomenon took place in the sky over Phoenix, Arizona. Thousands of people witnessed the occurrence, and a few dozen even caught it on camera. The event was so astonishing that the most world-renowned news source, CNN, broadcast it on national television. Disappearing, the mind-boggling event left thousands, or even millions, in disbelief at what they had just witnessed. What was it? The world may never know. The V-shaped object that appeared in the sky that night over Phoenix has left every UFO fanatic and scientist in awe. There is no real explanation for the bright lights that took the shape of a huge boomerang from 8:00 p.m. to 10:00 p.m. Many have tried to explain what no one can, but for every scenario, there is an equally crazy explanation that proves it to be false. To this day, there is still no explanation that is completely rock-solid and can explain this extremely odd occurrence. Have the inhabitants of Phoenix been the victim of a huge hoax, or have the people been witness to one of the most conclusive UFO sightings in history?  Witnesses There are many people throughout Arizona that say that they saw what is being called the Phoenix lights. Officials received calls and reports of the sighting from as far south as Tucson to the Northwestern reaches of Kingman. Dozens of people videotaped the action that was taking place, and a few even said that they saw the boomerang shaped UFO fly overhead before the sightings. News crews covered as many witnesses as they could find, trying to reveal some sort of clarity or explanation to what was seen to set every mind at ease. The most conclusive evidence of a UFO sighting came from a family that CNN interviewed and made their cover story. The Ley family says they saw the object fly overhead before any of the occurrences later that night. Tim Ley and his son said, "When it finally got here and we realized this thing was coming right over us, we really started getting antsy.
Monday, January 13, 2020
Examine the ecological impacts of global warming for Arctic areas Essay
Global warming is the general increase in average temperature globally over a period of time. This can have an effect on the arctic in a multitude of social, political and environmental ways For example, the Arctic Circle is home to over 150,000 Inuit’s, whose primary food source is fish and seals. As a result of global warming, arctic ice has receded greatly over the last 10 years, destroying seal hunting grounds, and so limiting access to Inuit food supply. Also, the melting of glaciers into the arctic waters is causing less fish to occupy the now fresh waters, causing polar bear and seal numbers to dwindle as there food source disappears. Such an impact to the Inuit food supply and main source of income would mean that communities would have to import food instead of hunting it, which would be incredibly expensive (up to USD$ 1 million per year) due to their high protein requirements to help them cope with the harsh environment. Another environmental impact is the negative feedback mechanism that artic ice withdrawal creates. Arctic ice has a high albedo, meaning it reflects a lot of solar radiation back into space. However, the sea and rock have a low albedo, meaning these areas are warmer. As a result of the ice melting, the general albedo of the arctic is lowering, which in turn causes an increase in average temperature, and therefore increases ice melting even more, and so on. This negative feedback mechanism will also further greenhouse gas emissions by the thawing of permafrost. Beneath the permafrost found on arctic tundra, are thousands of gallons of methane, trapped there for thousands of years. As this permafrost begins to melt, the methane will be released, increasing the temperature and creating a similar feedback mechanism to the albedo effect stated above. Further so, the warming of the arctic means that the â€Å"tree line†(the line at which most forests such as coniferous forests, stop growing) will recede. This withdrawal of the tree line means that habitats for creatures normally found in the northern parts of Russia and Greenland (or other arctic regions) will begin to inhabit further into the arctic, putting pressure on animals currently living in the arctic circle, for example the arctic fox. The melting of the arctic regions has also uncovered opportunity for oil companies such as BP and shell to start drilling for oil in regions they couldn’t previously drill in (for example the arctic pass). This increase in oil production can only further the greenhouse gas emissions, and spoil natural beauty of the area, and destroy habitats due to incidents such as oil spills (should they occur). Drilling is not the only risk that is imposed, as Russia have also allowed for nuclear waste disposal in there arctic territory, poisoning habitats and killing wildlife.
Sunday, January 5, 2020
Concert Critique The Houston Civic Symphony - 1078 Words
Jacqueline A. Vela 11/16/16 Music Appreciation MUSI 1306 ` Mr. Christopher Lee Concert Critique #1- The Houston Civic Symphony/50th Anniversary Season I have never attended an orchestral concert. Although my taste ranges between several different types of music, the only concerts I have attended are of the rock and country variety. I was not sure what to expect in attending The Houston Civic Symphony’s performance on Sunday, October 9, 2016. It was held at the Dunham Theater within the Morris Cultural Arts Center at Houston Baptist University. Once inside I saw the beautiful stage with all of the performers warming up and three stories of seating. Many of the patrons were in the age range of 30 and up. I did see some kids and young adults but not many. The HCS marked its 50th year since the very first performance this season. The first performance happened in 1996 when a group of music lovers in Houston came together to play a concert just because they wanted to play and share their love of music with others. From that day they became known as the Houston Civic Symphony. Some of the players I watched in this performance hav e been with the Symphony for 25 years or more while others are barely reaching their first year if not their first performance; only two of the players have been there since the very first season. Out of the three pieces performed the one that caught my attention the most was the last, it hold a powerful message of fear and desperation forShow MoreRelatedOrganisational Theory230255 Words  | 922 Pagespostmodernism anything new? The history Post-industrialism and the information society The virtual organization Neo-fordism, flexible specialization and post-fordism The regulation school Institutionalist school The ‘managerialist’ school The flexible firm – critique Postmodern organizations – the work of Stewart Clegg and Paul Heydebrand Conclusions 198 198 200 202 205 206 211 213 215 217 220 225 227 234 Chapter 6 Postmodernism as a philosophy: the ultimate challenge to organization theory? Introduction
Subscribe to:
Posts (Atom)