Sunday, September 22, 2019
Pharmacokinetics and pharmacodynamics of oral Metoprolol Essay Example for Free
Pharmacokinetics and pharmacodynamics of oral Metoprolol Essay The patient, Roger Smith, is a forty year old man and came to the doctors office yesterday morning presenting a chief complaint of on and off headaches. Every now and then he felt dizzy and would complain about blurred vision. He mentions that he does not have any allergies to food or medicines. He admits that he doesnt do any regular exercise. He favors salty food and eats plentiful of it everyday and prefers to drink alcohol two to three times per week. He was an only child and both his father and mother are deceased. The patients mother had hypertension and so did his mothers father. When he was a child he only had varicella zoster. He also mentioned that he sought medical attention a year ago and was diagnosed with essential hypertension. After that, the patient did not visit his previous doctor for a follow up on his medical health. The patient confesses that he did not follow his previous doctor’s prescription. Dr. Robert Jones, took the patients blood pressure and it read as 140/90 mm Hg. The patient was asked to undergo laboratory test for the patients blood creatinine (National Kidney Function, 2008). On the following day, Dr. Robert Jones, measured the patient’s blood pressure again and it read 140/90 mm Hg. The patient told the doctor that he took note of his blood pressure several days ago and it also had the same reading and it never went down. The doctor asked the patient to present him the laboratory result for the patients glomerular filtration rate. The glomerular filtration rate is the test to measure the patients kidney functions level. It is important to find out what the result is to prevent the progression of a kidney disease due to hypertension (National Kidney Function, 2008). The patients glomerular filtration rate value (GFR) was 72 mL/min/1.73 m2. The doctor interpreted to the patient that his glomerular filtration rate is normal and his kidneys are not affected yet by the hypertension. The GFR is calculated by the serum creatinine of the patient which is 1.4 mg/dL, the age of the patient is forty years old, the patients race is African American and the gender is male. The normal glomerular filtration rate value is 70  ± 14 mL/min/m2 for the male and 60  ± 10 mL/min/m2 for the female (National Kidney Function, 2008). The doctor explained that essential hypertension or primary hypertension is the blood pressure thats consistently higher than the normal value, 120/80 mm Hg, and there is no cause found for the high blood pressure. It can be controlled with normal exercise, a well-balanced diet, proper treatment and constant monitoring of the blood pressure. If it is left untreated, it will lead to heart attack, heart failure, damage to the kidney and it might cause the patient to lose his vision. (PSMHMC, 2006). The patient needs to lower the systolic and diastolic blood pressure (BP) to treat his hypertension as this is an important cardiovascular risk factor (Koenig, 2001). The doctor educated the patient to maintain his weight level near to the normal and eat a well-balanced diet. He was instructed to limit the salt intake everyday to 2,000mg or even lower. Exercise regularly and avoid drinking too much alcohol and limit the intake of caffeine. All these are needed to be followed to control the blood pressure. The patient was also educated about taking care of his blood pressure because it will cause the kidney to fail. In order to prevent this from happening, his blood pressure must be controlled (DailyMed, 2006). The doctor prescribed the patient to take metoprolol tartrate 100mg for the first four weeks and then increased the dose to 200mg for another four weeks. The patient is instructed to orally take metoprolol once daily (Koenig, 2001). Metoprolol is a beta-adrenergic blocking agent that decreases the heart rate, decreases the contraction force of the heart muscle and it lowers the the blood pressure. Metoprolol targets the sympathetic nervous system by blocking its action in order to stimulate the heart beats pace. (Hildemann, et. al., 2002). The doctor further explained that metoprolol helps relax the blood vessels and will help the heart beat at a more regular rate. In this way, high blood pressure is reduced. Other heart diseases, for example stroke or heart attack will be prevented (Koenig, 2001). The medicine is taken through the mouth and will pass through the digestive tract before it can reach the bloodstream for absorption. The onset of action of metoprolol as an anti-hypertensive if taken orally is 1 1/2 to 4 hours. It will last for ten to twenty hours and will be absorbed at a percentage of 95%. For its metabolism, it is extensively hepatic through CYP2D6; significant first-pass effect. The half-life elimination period is three to four hours (Koenig, 2001). Metoprolol will be excreted through the urine with the percentage of 3% to 10% as an unchanged drug (DailyMed, 2006). According to the explanation of the doctor, metoprolol is metabolized in the liver by the cytochrome P450 2D6. Therefore, metabolization of the drug depends on the genetic polymorph that determines the hepatic hydroxylation rate. Metoprolol is excreted by the kidney as metabolites and is absorbed within seventy-two hours by glomerular filtration. The patient is further informed that while he is taking metoprolol, he is advised not to take in any other medicine. He should follow the correct dosage at the right time, in other words, the patient is not allowed to change the dosage or the time hes supposed to take the medicine. The medicine should not be taken in with an antacid (DailyMed, 2006). The patient will feel fatigue or dizziness. He should inform the doctor any changes like unusual weight gain or muscle fatigue, swellings of any part the extremities, constipation or should he develop a cough. The patient should maintain a blood pressure of less than 140/90mm Hg. He should take his pulse prior to taking metoprolol orally. The patient will be able to keep himself healthy and fit if he continues to follow the doctors prescription. The systolic and diastolic blood pressure (BP) will be lower when the patient follows the intake of metoprolol as prescribed by the doctor (Koenig, 2001). After eight weeks, the patient came to visit Dr. Robert Jones and had his blood pressure is already 120/80 and his glomerular filtration rate value remains at the normal level. The patient is instructed by the doctor to constantly maintain a healthy diet, regularly exercise and take note of his blood pressure everyday (Koenig, 2001). References: Dailymed (2006). METOPROLOL TARTRATE and HYDROCHLOROTHIAZIDE      TABLETS, USP50 mg/25 mg, 100 mg/25 mg and 100 mg/50 mgBeta      Blocker/Diuretic Antihypertensive. Retrieved February 8, 2008, from      http://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?id=2522type=display Indian Journal of Pharmacology. (2008) Metoprolol Pindolol: A comparative study in      essential hypertension. Retrieved February 8, 2008, from http://www.ijp-online.com/article.asp?issn=02537613;year=1990;volume=22;issue=2;spage=85;epage=88;aulast=Gugli;type=0 S.K. Hildemann, H. Fischer, D. Pittrow, V. Bohlscheid (2002). Metoprolol Succinate SR Plus           Hydrochlorothiazide (Beloc-Zok ® Comp) in Patients With Essential Hypertension in      General Practice. Medscape Today. Retrieved February 10, 2008, from      http://www.medscape.com/viewarticle/444414_1 Penn State Milton S. Hershey Medical Center College of Medicine (2006). Essential      Hypertension. Retrieved February 10, 2008, from      http://www.hmc.psu.edu/healthinfo/e/essentialhypertension.htm National Kidney Function (2008). Glomerular Filtration Rate (GFR). Retrieved from      February 10, 2008, http://www.kidney.org/kidneydisease/ckd/knowGFR.cfm Wolfgang Koenig, on behalf of the Multicentre Study Group, Department of Internal      Medicine II-Cardiology, University of Ulm Medical Center, Ulm, Germany      (2001). Efficacy and Tolerability of Metoprolol Tartrate in Patients With Mild-to-      Moderate Essential Hypertension: A Randomised, Double-Blind, Multicentre      Trial. Retrieved from February 10, 2008, from      http://www.medscape.com/viewarticle/406240
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