Atenolol is a cardioselective but not cardiospecific beta-blocker. A low dose (<100 mg / day) is cardioselective, it preferentially inhibits the cardiac beta 1 receptors with a duration of action of more than 24 hours. At high doses (> 100 mg / day) also it blocks beta 2 receptors localized in vascular and bronchial asthma. Beta adrenergic receptors are also present in pancreas and liver. Atenolol is devoid of intrinsic sympathomimetic activity (does not have partial effect of beta-agonist) and membrane stabilizing activity.
The atenolol is used in the treatment of hypertension, myocardial infarction and angina attacks.
Atenolol Metabolome Database
It is rapidly absorbed in the gastro-intestinal tract, reaching maximum plasma concentration from 2 to 4 hours after administration. The high hydrophilicity, makes the pharmacokinetics of this agent rather linear and constant between individuals, reducing to a minimum the hepatic metabolism and the passage through the barriers (membranes) biological. After plasma half-life of 6/9 hours, atenolol is generally excreted unchanged in the urine.
Studies on the pharmacokinetics and pharmacodynamics of atenolol in man. European Journal of clinical pharmacology. 1978. Fitzgerald et all.
As with other beta-blockers, atenolol interferes with gluconeogenesis. May mask the tachycardia, palpitations, instability pressure, tremor and anxiety caused by hypoglycemia in case of patients suffering from diabetes mellitus; could precipitate crisis hyperglycemic for inhibition of glicogenolisi.Occasionalmente can cause phenomena of hyperglycemia, due might block beta 2 receptors present on pancreatic cells, resulting in inhibition of insulin secretion. In these cases it is advisable to monitor blood glucose levels (use of beta-blockers in patients with diabetes mellitus).
Cardiovascular morbidity and mortality in patients with diabetes in the Losartan Intervention For Endpoint reduction in hypertension study (LIFE): a randomized trial against atenolol. Lancet. 2002. Lindholm et all
Atenolol increased levels of triglycerides and decreases the concentration of free fatty acids.
The atenolol suppresses the release of renin from the kidneys; blocks the mechanism of lipolysis induced by catecholamines with consequent decrease in the synthesis of arachidonic acid and prostaglandin.
The drug inhibits platelet aggregation by decreasing prostaglandin and block platelet adhesion induced by catecholamines.
Other actions of atenolol include the prevention of the release of epinephrine during coagulation and an increased release of oxygen to tissues.
Like other beta-blockers without intrinsic sympathomimetic activity (ISA) can cause sexual dysfunction
Main side effects associated with beta-blocker therapy, including hypotension, asthenia, bronchospasm, cold extremities, insomnia and nightmares, and sexual dysfunction
The tolerability of atenolol (doses of 50 and 100 mg) was comparable to that of captopril, enalapril); bisoprolol, bopindololo, pindolol, bevantolol, nicardipine, nifedipine (in case of angina pectoris).
Some doctors prescribe beta blockers to lower blood levels of testosterone.
Effect of antihypertensive treatment with valsartan or atenolol on sexual activity and plasma testosterone in hypertensive men.Eur J Clin Pharmacol. 2002 . Fogari et all
Effect of beta adrenergic antagonist on the production of testosterone by rat Leydig's cells. J Ayub Med Coll Abbottabad.2004. Khan et all
Probably cAMP - PKa pathway is inhibited at the level of Leydig cells that exhibit beta-adrenergic receptors on their surface. The use of beta blockers seems to lead to a down-regulation of adrenergic receptors as long as the dose of drug is maintained constant over the time. In addition, the hiring and termination of treatment should be conducted in a gradual manner to avoid heart disease (eg, syncope).
Alternative antihypertensive drugs with lower risk of erectile dysfunction are alpha-blockers, ACE inhibitors and calcium channel blockers. Particular attention should be paid also to thiazide diuretics such as hydrochlorothiazide (Esidrex), the mechanism by which these drugs cause erectile dysfunction is not clear, however it is estimated that in 10-20% of patients treated with thiazide diuretics has dysfunction dysfunction. In one clinical study, it was verified that the occurrence of erectile dysfunction coincides with a zincuria induced by the drug that causes reduction in the concentrations of zinc in the blood. In this study the introduction of zinc as a supplement leads to an improvement of sexual function in approximately 50% of patients presenting with erectile dysfunction.
The use of drugs cardioselective beta blockers is indicated in diseases such as hypertension, angina, myocardial infarction, arrhythmias, cardiac failure and thyrotoxicosis. However, 25% of patients receiving beta-blocker complains serious disturbances in the sexual sphere that often lead to discontinuation of therapy by the treating physician. In some particular clinical cases (mainly heart failure) their use can not be vicariate in any way, so there are no viable alternatives in the event appear unwanted side effects.
Their use is often accompanied intake of ACE inhibitors, causing dizziness and hypotension in the subject: low blood pressure is not considered a serious side effect.
The use of beta blockers in the case of heart disease is often presented as an improvement in the quality of life of the individual. Some aspects, of course, will come to be improved (eg cease part of the sensation of breathlessness after a short distance flight of stairs), but with the importance of sexuality in achieving a feeling of fulfillment in one's life, the use of these drugs should be careful and scrupulous.
Sexual dysfunction is also often accompanied by a decrease of desire and libido, in both men and women undergoing this treatment.
A study, made in 2004, investigates how atenolol cause a significant loss of libido in postmenopausal women compared with treatment with a second group with Valsartan (Angiotensin II receptor inhibitor), which has even been shown to increase the satisfaction and levels of sexual desire .
Effect of valsartan and atenolol on sexual behavior in hypertensive postmenopausal women. Am J Hypertens.2004.Fogari et all
The huge increase in sales of vasoactive drugs linked to the achievement of satisfactory sexual performance (Viagra, Cialis, Levitra) indicates how sex has reached a prominent place in the life of the individual, that despite his advanced age, or the combination of sexual dysfunctions first disabling, does not want to give up this aspect of his existence. This phenomenon has played a part in the clearance of media sex and the partial weakening of a culture that brought with it the legacy of Puritanism church as an example to future generations.
The change in the customs and habits should make us reconsider the medical approach during the administration of drugs that, very often, to solve a physical problem, create dissatisfaction or unhappiness in the emotional part of the person