Beta Blockers Properties Of Propranolol And Atenolol Biology Essay

Beta Blockers Properties Of Propranolol And Atenolol Biology EssayAbstr get alongThis quiz reports the properties of propranolol (lipophilic 1-selective blocker) and atenolol (hydrophilic 1-selective blocker) in the point of view of pharmacology, pharmacokinetics, and physical chemistry. It is observed that their pharmacological and pharmacokinetic properties are different, but its physicochemical properties are relative close.Introduction to -blockersThe -blockers are drugs which act by blocking the erect of mediators and agonists on the relevant receptors. The -blockers immortalize an antihypertensive effect, which is fixd by reduced cardiac output, change magnitude release of renin, central decrease of pitying action. Also, they exhibit an antianginal effect, which is ca apply by slowing of the heart rate and thus decreased metabolic demand. The main side effects of general -blockers are cardiac failure, such(prenominal) as cardiac depression, hypotension, sinus node dysfunc tion, atrioventricular block. The side effects depend on the properties of -blockers. For instance, non-selective -blockers show the unwanted effects caused by blocking 2-receptor. These show bronchoconstriction which is potentially life-threatening in asthmatic patients and clinically undesirable in patients with other respiratory problems. Lipophilic -blockers may cause psychological symptoms, such as depression.There are some important factors in the selection of -blockers, which are ISA, MSA, 1-selectivity, lipophilicity, solubility, and the duration of effects. The 2-selective blockers are non used clinically, because of causing bronchoconstriction. Some -blockers show the effect of not only blocking the receptors, but also stimulating -receptors. It depends on the situation whether ISA positive -blockers stimulate or block -receptors. For example, these act as -blockers to a lower place the existence of -agonists. On the other hand, these invigorate the receptors under the n on-existence of -agonists. Such an effect is termed ISA which is intrinsic sympathomimetic activity. The drugs which have ISA decrease the side effects caused by -blockers. The non-selective blocks of -receptors cause the increase in cardiac afterload and bronchocostriction, because of 2-blocking. The 1-selective drugs slightly have the effect of 2-blocking, but the risk of causing cardiac afterload and bronchoconstriction is lower than that of non-selective -blockers. The duration of effects depends on the disease. want acting -blockers are desirable for hypertension and heart failure, because of the low frequency of administration. In contrast, short acting -blockers, propranolol, are ideal drugs for angina, because of the fast onset of action. As I stated above, lipophilic -blockers have a risk of causing depression. The reason is such drugs are absorbed easily, so can penetrate BBB. MSA, membrane stabilising activity, is an activity which prevents sodium ions from entering ins ide of cells. Many -blockers, such as propranolol, have the activity, so these are useful for arrhythmia.The properties of propranololPropranolol is a non-selective -blocker, which is clinically used as propranolol hydrochloride. The IUPAC name is (2RS)-1-(1-Methylethyl) amino-3-(naphthalen-1-yloxy) propan-2-ol monohydrochlorid. The molecular weight is 295.80, and the melting point is around 165 degrees. It is white crystalline powder, and it is easy to dissolve in water and wood spirit. Also, the methanol solution doesnt exhibit optical activity. Its structural formula is following.Propranolol is absorbed from the gastrointestinal tract, its plasma level reach a peak, 42.9ng/ml, after 1.5 hours of administration. The half(a) life is roughly 3.9 hours. The metabolism of propranolol is mainly conducted by the liver, so it is metabolised to naphthoxylactic acid, glucuronic acid conjugate, and 4-Hydroxypropranolol. It is mainly metabolised by CYP2D6, CYP1A2, and CYP2C19. As I discu ssed above, propranolol can penetrate BBB and transition to the oral sex, because of lipophilic. Its dosage amount is broadly speaking excreted in urine within 48 hours, and the rest is excreted in faeces, which is just less than 4 percentages. Its pharmacological actions include an antihypertensive effect, an antianginal effect, and MSA. Propranolol doesnt show ISA in the prove with using rats, so it is considered that propranolol doesnt show human ISA as well as rats. Some side effects have been reported, such as, bronchoconstriction, slowing of heart rate, and allergic. These days, a new side effect is becoming popular, which is mental symptoms, such as depression, nightmare, and insomnia. There is the drug-drug interaction in propranol. For instance, propranolol lurch use with thioridazine which is a mind-bending drug, especially for integration dysfunction symptom. The reason is the side effect of thioridazine is likely to happen, because of preventing propranolol from bei ng metabolised thioridazine by enzymes in the liver. In the same way, propranolol cant use with rizatriptan which is a drug for migraine. Combination use with propranolol and rizatoriptan induce the extension of half life of and the increase of AUC, so increase the side effects. Also, it is essential to exclude administering rizatoriptan within 24 hours of administration of propranolol for the same reason. Its package leaflet approved by US Food and Drug Administration warns.Therefore, its administration should not be stopped suddenly. Above statement is one of the most important warnings in the usage of propranolol.Properties of atenololAtenolol is a 1-selective blocker without showing MSA and ISA, which is used for hypertension, angina, and cardiac dysrhythmias. It is sold as TENORMIN in the market. The IUPAC name is 2-(4-(2RS)-2-Hydroxy-3-(1-methylethyl) amino propyloxy phenyl) acetamide. The molecular weight is 266.34, and the melting point is around 155 degrees. It is white or light xanthous crystalline powder, and it is easy to dissolve in water and methanol as well as propranolol. In addition, the methanol solution doesnt exhibit optical activity. Its structural formula is following.Atenolol is almost half absorbed from gastrointestinal tract, and the rest enter systemic circulation without getting first pass effect on the liver. Its half life is approximately 7 hours. Atenolol is little metabolised in the liver, but some are metabolised to glucuronic acid conjugate. The data shows that atenolol is low distribution to brain compared to proranolol, because its drug is hydrophilic. Therefore, it has been reported that atenolol hardly have an influence on mental symptom unlike propranolol. The excretion of oral atenolol is approximately 50% in urine and faeces respectively, but 90% of them are not metabolised. As I stated above, atenolol is a 1-selective blocker, so it is little to alter bronchial tubes which is controlled by 2-receptor. However, the da ta have been reported atenolol inhibit 2-receptor at high dose. Its side effects are almost the same as propranolol. The main going away between atenolol and propranolol is the incidence of tracheal symptoms, such as bronchoconstriction and bronchial spasm. Propranolol blocks -receptors non- selectively, so causes different tracheal symptoms. In contrast, atenolol inhibits 1-receptors selectively, so barely makes such symptoms happen. The sudden cessation of therapy with atenolol has a possibility of causing cardiac diseases for specific patients. Its leaflet approved by FDA cautions,The properties of -blockers in telling patientsThese days, the number of obese people is increasing due to high calorie foods and the decrease of exercise. It is common for obese patients to take drug therapy in clinical practice, because obesity is connected with many diseases, such as diabetes and cardiovascular disease. Therefore, it is important to identify pharmacological and pharmacokinetic prop erties in obese patients. Jerzy Wojcickia studied the pharmacological and pharmacodynamic properties between propranolol and atenolol in obese patients. As a result, he concluded following.ConclusionIn summary, there are some differences between propranolol and atenolol from the point of view of pharmacology, because of the difference of selectivity of -receptor. In the same way, there are some pharmacokinetic differences as well, such as the duration of half life and the mechanism of metabolism and excretion. In contrast, their physicochemical properties are similar. In clinical use, there are some warnings respectively, and the common cautions are to avoid sudden discontinuation of administration. Its dosage should be progressively decreased over a few weeks in order to avoid such side effects. I studied the characters between these -blockers in obese patients. In the study, it was not observed there are the obvious differences between obese patients and non-obese patients