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Amlodipine with Atenolol

Indication

  • Hypertension
  • Chronic stable angina

Dosage and Administration

The recommended dosage is one tablet daily. If necessary, the dosage may be increased to two tablets daily. The dosage however should be individualized.

Renal lmpairment
Dosage should be adjusted in cases of severe impairment of renal function. Dosage of atenolol should not exceed 50 mg/day when creatinine clearance is 15-35 ml/min/1.73 m2. While in patients with creatinine clearance<15 ml/min/1.73 m2, the maximum dosage of atenolol should be 25 mg/day.

Hepatic impairment
The recommended initial dose in patients with hepatic impairment is half tablet.

Elderly patients
Dose selection for an elderly patient should be cautious, usually starting at half tablet.

Contraindications

Hypersensitivity to either component, sinus bradycardia, second and higher degrees of heart block, cardiogenic shock, hypotension and overt cardiac failure.

Warnings and Precautions

Pregnancy
The combination should be used during pregnancy only if the expected benefit outweighs the potential fetal risk.

Lactation
The combination should not be used by nursing mothers. If its use is considered necessary, breast feeding should be stopped.

Pediatric use
Safety and effectiveness of this combination has not been evaluated in pediatrics.

Geriatric Use
In general, dose selection should be done with caution in elderly patients, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease other drug therapy.

Renal Impairment
Since atenolol is excreted via the kidneys, dosage of atenolol should be reduced in patients with a creatinine clearance <35 ml/min/1.73 m2.

Hepatic Impairment
Caution may be necessary in the use of the combination in patients with severe liver damage because of the prolongation of the elimination half-life of amlodipine.

Hypotension
Excessive fall of blood pressure can occur in some patients especially the elderly.

Aggravation of Angina
Rarely patients, particularly those with severe obstructive coronary artery disease, have developed increased frequency, duration and/or severity of angina or acute myocardial infarction on starting calcium channel blocker therapy or at the time of dosage increase.

Congestive Heart Failure
In general, calcium channel blockers should be used with caution in patients with heart failure. Placebo-controlled trials of amlodipine in patients with New York Heart Association (NYHA) Class III or IV heart failure showed no overall adverse effect on survival or cardiac morbidity. In NYHA class II/III heart failure patients, there was no evidence of worsened heart failure based on measures of exercise tolerance, NYHA classification, symptoms or left ventricular ejection fraction (LVEF).

Sympathetic stimulation is necessary in supporting circulatory function in congestive heart failure, and beta blockade carries the potential hazard of further depressing myocardial contractility and precipitating more severe failure. In patients who have congestive heart failure controlled by digitalis and/or diuretics, atenolol should be administered cautiously. Both digitalis and atenolol slow AV
conduction.

In Patients without a History of Cardiac Failure
Continued depression of the myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure. At the first sign or symptom of impending cardiac failure, patients should be treated appropriately according to currently recommended guidelines, and the response observed closely. If cardiac failure continues despite adequate treatment, AMLOPRES-AT should be
withdrawn.

Bronchospasm
The combination should be used with caution in patients with airway obstruction who do not respond to, or cannot tolerate, other antihypertensive treatment.

Cessation of Therapy
Patients with coronary artery disease, who are being treated with amlodipine+atenolol, should be advised against abrupt discontinuation of therapy. Severe exacerbation of angina and the occurrence of myocardial infarction and ventricular arrhythmias have been reported in angina patients following the abrupt discontinuation of therapy with beta-blockers. The last two complications
may occur with or without preceding exacerbation of the angina pectoris. When discontinuation of amlodipine+atenolol is planned, as done during every beta-blocker withdrawal, the patients should be carefully observed and advised to limit physical activity to a minimum. If the angina worsens or acute coronary insufficiency develops, it is recommended that amlodipine+atenolol be promptly reinstituted, at least temporarily. Because coronary artery disease is common and may be unrecognized, it may be prudent not to discontinue amlodipine+atenolol therapy abruptly even in patients treated only for hypertension.

Anaesthesia and Major Surgery
It is not advisable to withdraw amlodipine+atenolol prior to surgery in the majority of patients. However, care should be taken when using anaesthetic agents such as those, which may depress the myocardium. Atenolol is a competitive inhibitor of beta-receptor agonists and its effects on the heart can be reversed by administration of such agents: eg, dobutamine or isoproterenol with caution.

Diabetes and Hypoglycaemia
Amlodipine+atenolol should be used with caution in diabetic patients if a betablocking agent is required. Beta-blockers may mask tachycardia occurring with hypoglycaemia, but other manifestations such as dizziness and sweating may not be significantly affected. At recommended doses atenolol does not potentiate insulin-induced hypoglycaemia and, unlike nonselective beta-blockers, does not delay recovery of blood glucose to normal levels.

Thyrotoxicosis
Beta-adrenergic blockade may mask certain clinical signs (eg, tachycardia) of hyperthyroidism. Abrupt withdrawal of beta blockade might precipitate a thyroid storm; therefore, patients suspected of developing thyrotoxicosis from whom amlodipine+atenolol therapy is to be withdrawn should be monitored closely.

Untreated Phaeochromocytoma
Amlodipine+atenolol should not be given to patients with untreated phaeochromocytoma.

Aortic Stenosis
Caution should be exercised when administering AMLOPRES-AT in patients with severe aortic stenosis.

Drug Interactions

Catecholamine depleting drugs: Coadministration with catecholamine depleting drugs (eg. reserpine) may have additive effect when given with betablocker, and hence patients taking both the drugs concomitantly should be observed for hypotension and/or marked bradycardia.

Clonidine: Beta-blockers may exacerbate the rebound hypertension, which can follow the withdrawal of clonidine. If the two drugs are coadministered, amlodipine+atenolol should be withdrawn several days before the gradual withdrawal of clonidine. If replacing clonidine by amlodipine+atenolol, the introduction of amlodipine+atenolol should be delayed for several days after clonidine administration has stopped.

Prostaglandin synthase inhibiting drugs: Concomitant use of prostaglandin synthase inhibiting drugs, e.g., indomethacin, may decrease the hypotensive effects of beta-blockers.

Side effects

The combination of amlodipine and atenolol is well tolerated. Side effects include headache, palpitations, flushing, edema, depression, dizziness, dyspepsia, dyspnoea, muscle cramps, fatigue, cold extremities and bradycardia.

Overdosage

Amlodipine
If massive overdose should occur, active cardiac and respiratory monitoring should be instituted. Frequent blood pressure measurements are essential.
Should hypotension occur, cardiovascular support including elevation of the extremities and the judicious administration of fluids should be initiated. If hypotension remains unresponsive to these conservative measures, administration of vasopressors (such as phenylephrine) should be considered with attention to circulating volume and urine output. Intravenous calcium gluconate may help to reverse the effects of calcium entry blockade. As amlodipine is highly protein bound, hemodialysis is not likely to be of benefit.

Atenolol
The predominant symptoms reported following atenolol overdose are lethargy, disorder of respiratory drive, wheezing, sinus pause and bradycardia.
Additionally, common effects associated with overdosage of any beta-adrenergic blocking agent and which might also be expected in atenolol overdose are congestive heart failure, hypotension, bronchospasm and/or hypoglycemia. Treatment of overdose should be directed to the removal of any unabsorbed drug by induced emesis, gastric lavage, or administration of activated charcoal.
Atenolol can be removed from the general circulation by hemodialysis. Other treatment modalities should be employed at the physician' discretion and may include:
Bradycardia: Atropine intravenously. If there is no response to vagal blockade, give isoproterenol cautiously. In refractory cases, a transvenous cardiac pacemaker may be indicated.
Heart block (second or third degree): Isoproterenol or transvenous cardiac pacemaker.
Cardiac failure: Digitalize the patient and administer a diuretic. Glucagon has been reported to be useful.
Hypotension: Vasopressors such as dopamine or norepinephrine (levarterenol).
Monitor blood pressure continuously.
Bronchospasm: A beta2 stimulant such as isoproterenol or terbutaline and/or aminophylline.
Hypoglycemia: Intravenous glucose.

 


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