Sotalol

Sotalol is a nonselective beta-adrenergic blocking agent belonging to the beta-blocker class.

Sotalol is approved for the treatment of hemodynamically stable ventricular tachycardia and paroxysmal atrial fibrillation. It is also used to treat sinus rhythm, postoperative atrial fibrillation after cardiac surgery, and supraventricular tachycardia.

Sotalol is nearly completely absorbed after the oral administration and undergoes essentially no first-pass hepatic metabolism. As a result, its absolute bioavailability is 90–100%. The apparent volume of distribution of sotalol is 1.2-2.4L/kg. Sotalol is not metabolized and 80-90% of a given dose is excreted in the urine as unchanged sotalol. A small fraction of the doses is excreted in feces as unchanged sotalol.

The common side effects associated with Sotalol include insomnia, muscle pain, dizziness, fatigue, elevated liver enzymes, joint pain, abdominal discomfort, paresthesias, bradycardia, cold extremities, and hypotension.

Sotalol is available in the form of tablets and injectable solutions. 

Sotalol is available in India, Canada, Switzerland, and the USA.

Sotalol, belonging to the beta blocker, acts as a nonselective beta-adrenergic blocker. Sotalol works by changing the way the body responds to some nerve impulses, especially in the heart. It slows down the heart rate and makes it easier for the heart to pump blood around the body.

It works by blocking abnormal electrical signals in the heart, which helps control the heart's uneven beating by inhibiting beta-1 adrenoceptors in the myocardium as well as rapid potassium channels to slow repolarization, lengthen QT interval, and slow and shorten the conduction of action potentials through the atria.

The onset of action of Sotalol occurs within 1-2 hours for oral and approx. 5-10 minutes for IV.

The Duration of Action for Sotalol in the body is 8-16 hours.

The Tmax was found within 2-4 hours following the administration of Sotalol and Cmax was about 320 to 640 mg/day.

Sotalol is available in the form of tablets, oral solutions, and injectable solution

Tablets:

Sotalol tablets to be swallowed whole with water. Sotalol comes as a tablet to be taken by mouth. It is usually taken two times a day.

Oral Solution:

• Use the dropper that comes with the package to measure the dose.

• Adults and adolescents: Drop the liquid directly into the mouth or mix it with food or other liquids (e.g., water or juice).

Injectable Solution:

• Intravenous sotalol must be diluted for infusion.
• Dilute IV sotalol in saline, 5% dextrose in water (D5W), or Ringer's lactate.
• Use a volumetric infusion pump.

Sotalol is a nonselective beta-adrenergic blocking agent belonging to the beta-blocker class.

Sotalol is approved for the treatment of hemodynamically stable ventricular tachycardia and paroxysmal atrial fibrillation. It is also used to treat sinus rhythm, postoperative atrial fibrillation after cardiac surgery, and supraventricular tachycardia.

Sotalol inhibits beta-1 adrenoceptors in the myocardium as well as rapid potassium channels to slow repolarization, lengthen the QT interval, and slow and shorten the conduction of action potentials through the atria. The action of sotalol on beta-adrenergic receptors lengthens the sinus node cycle, conduction time through the atrioventricular node, refractory period, and duration of action potentials.

Sotalol is approved for use in the following clinical indications

Ventricular Tachycardia:

Sotalol is indicated for the treatment of life-threatening ventricular tachycardia. Antiarrhythmic drugs may not enhance survival in patients with ventricular arrhythmias.

Atrial Fibrillation/Atrial Flutter:

Sotalol is indicated for maintenance of the normal sinus rhythm [delay in time to recurrence of the atrial fibrillation/atrial flutter (AFIB/AFL)] in patients with symptomatic AFIB/AFL who are currently in sinus rhythm.

Although not approved, there have been certain off-label uses documented for Sotalol. These include:

• Premature ventricular contractions-sotalol has been superior to placebo for suppressing premature ventricular contractions.
• Pharmacological cardioversion of atrial fibrillation-less effective.
• Postoperative atrial fibrillation after cardiac surgery.
• Supraventricular tachycardia- especially when administered intravenously.
• Transplacental isolated sotalol or in conjunction with digoxin to treat fetal SVT and atrial fibrillation with 85% complete or partial resolution.

Sotalol is available in the form of tablets, oral solutions, and injectable solutions.

For Oral Dosage:

Ventricular arrhythmias:

• 80 mg taken by mouth twice a day; may increase by increments of 80 mg/day for every three days if QTc <500 msec
• Monitor until steady-state levels are achieved; therapeutic dose is usually obtained at the total daily dose of 160-320 mg/day divided by twice a day or either three times a day
• Doses of 480-640 mg/day have been utilized with refractory life-threatening arrhythmias.

Atrial fibrillation/flutter:

• 80 mg taken by mouth twice a day; may increase by increments of 80 mg/day every 3 Days if QTc <500 msec
• Monitor until steady-state levels are achieved; the typical dose is 120 mg twice a day.
• Initiation of sotalol in patients with creatinine clearance <40 mL/min or QTc >450 msec is contraindicated

Use of IV for substitution of Oral dosage form:

• To match the exposure to oral sotalol, use the same dosing frequency with IV administration and infuse the adjusted dose over 5 hr
• For 80 mg taken by mouth: Substitute 75 mg IV
• For 120 mg taken by mouth: Substitute 112.5 mg IV
• For 160 mg taken by mouth: Substitute 150 mg IV

Sotalol can be administered orally before/ after meals. The dosage and the duration of treatment should be as per the clinical judgment of the treating physician.

Sotalol is available in various dosage strengths as 80 mg, 120 mg, 160 mg, 240 mg, 5 mg/ml, 15 mg/ml.

Sotalol is available in the form of tablets, oral solutions, and injectable solutions.

Sotalol is approved for the treatment of hemodynamically stable ventricular tachycardia and paroxysmal atrial fibrillation.

• Ventricular tachycardia: It has been observed that the low-salt Dietary Approaches to Stop Hypertension (DASH) diet lowers blood pressure. Sometimes after a few weeks, its effects on blood pressure become noticeable.

• Atrial Fibrillation: Some foods can negatively affect your heart health and have been shown to increase the risk of heart complications. Diets high in processed foods, such as fast food, and items high in added sugar, like soda and sugary baked goods, have been linked to increased heart disease risk They can also lead to other negative health outcomes like weight gain, and diabetes, cognitive decline, and certain cancers.

The dietary restriction should be individualized as per patient requirements

Sotalol may be contraindicated in the following:

Non-cardioselective Beta-blockade

• Bronchial asthma or other bronchospastic conditions
• Sinus bradycardia
• 2nd or 3rd degree AV block absent a functioning pacemaker
• Cardiogenic shock
• Decompensated heart failure due to a negative inotropic effect
• Sick sinus syndrome (without a pacemaker)
• Labile diabetes (due to hypoglycemia)
• Left ventricular hypertrophy (which also increases the risk of arrhythmia)

QTc Prolonging Effects

• CrCl < 40 ml/min when used for atrial fibrillation or flutter
• Acquired or congenital long QTc syndromes
• Uncorrected hypokalemia or hypomagnesemia (increased risk of prolonging QT and causing torsades de pointes)

Other Contraindications

• Previous evidence of sotalol hypersensitivity or allergy

The treating physician must closely monitor the patient and keep pharmacovigilance as follows

• Proarrhythmia

Sotalol can cause serious ventricular arrhythmias, primarily Torsade de Pointes (TdP) type ventricular tachycardia, a polymorphic ventricular tachycardia associated with QTc prolongation. QTc prolongation is directly related to the concentration of sotalol. Factors such as decreased creatinine clearance, gender (female) and higher dose, bradycardia, history of sustained VT/VF, atrial fibrillation with sinus node dysfunction, and heart failure increase the risk of TdP. The risk of TdP can be reduced by the adjustment of sotalol dose according to the creatinine clearance and by monitoring the ECG for excessive increases in QTc. Correct hypokalemia or hypomagnesemia prior to initiating sotalol hydrochloride, as these conditions can exaggerate the degree of QT prolongation and increase the potential for TdP. Special attention should be given to electrolyte and acid-base balance in patients experiencing severe or prolonged diarrhea or patients receiving concomitant diuretic drugs. Avoid sotalol with other drugs known to cause QT prolongation

• Bradycardia/Heart Block

Sotalol can cause bradycardia, sinus pauses, or sinus arrest. Sotalol-induced bradycardia increases the risk of Torsade de Pointe, particularly the following cardioversion. Monitor the ECG in patients receiving concomitant negative chronotropes

• Sick Sinus Syndrome

In general, sotalol is not recommended in patients with sick sinus syndrome associated with symptomatic arrhythmias, because it may cause sinus bradycardia, sinus pauses, or sinus arrest. Sotalol augments bradycardia and QTc prolongation following cardioversion. Patients with AFIB/AFL associated with sick sinus syndrome may be treated with sotalol if they have an implanted pacemaker for control of bradycardia symptoms.

• Hypotension

Sotalol produces significant reductions in both systolic and diastolic blood pressures. Monitor hemodynamics during administration.

• Heart Failure

New onset or worsening heart failure may occur during initiation or up-titration of sotalol because of its beta-blocking effects. Monitor for signs and symptoms of heart failure and discontinue treatment if symptoms occur.

• Bronchospasm

Avoid beta-blockers, like sotalol, in patients with bronchospastic diseases. If sotalol is required, use the smallest effective dose.

• Masked Signs of Hypoglycemia in Diabetics

Beta-blockade may mask tachycardia occurring with hypoglycemia, but other manifestations such as dizziness and sweating may not be significantly affected. Diabetic patients may experience elevated blood glucose levels and increased insulin requirements.

• Thyroid Abnormalities

Avoid abrupt withdrawal of beta-blockade which might be followed by an exacerbation of symptoms of hyperthyroidism, including thyroid storm. Beta-blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism.

• Anaphylaxis

While taking beta-blockers, patients with a history of anaphylactic reaction to a variety of allergens may have a more severe reaction to repeated challenges, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat the allergic reaction.

• Anesthesia

The impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.

The adverse reactions related to the molecule Sotalol can be categorized as

• Common Adverse effects:

Bradycardia, headache, Dizziness, fatigue, etc.

• Less Common adverse effects:

Nervousness, Elevated liver enzymes, joint paint, edema, vivid dreams, abdominal discomfort, nausea, muscle cramps, paresthesias, bradycardia, cold extremities, hypotension, palpitations, syncope, Anxiety, lethargy, diarrhea, vomiting, Impotence/reduced libido.

• Rare adverse effects:

Heart failure, tachyarrhythmia, bronchospasm, depression, decreased exercise tolerance, Raynaud's phenomenon, etc.

The clinically relevant drug interactions of Sotalol are briefly summarized here:

• Negative Chronotropes

Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia.

• Calcium Blocking Drugs

Sotalol and calcium blocking drugs can be expected to have additive effects on atrioventricular conduction, ventricular function, and blood pressure.

• Catecholamine-Depleting Agents

Concomitant use of catecholamine-depleting drugs, such as reserpine and guanethidine, with a beta-blocker may produce an excessive reduction of resting sympathetic nervous tone. Monitor such patients for hypotension and marked bradycardia which may produce syncope.

• Insulin and Oral Antidiabetics

Hyperglycemia may occur, and the dosage of insulin or antidiabetic drugs may require adjustment. Symptoms of hypoglycemia may be masked.

• Beta-2-Receptor Stimulants

Beta-agonists such as albuterol, terbutaline, and isoproterenol may have to be administered in increased dosages when used concomitantly with sotalol.

• Clonidine

Concomitant use with sotalol increases the risk of bradycardia. Because beta-blockers may potentiate the rebound hypertension sometimes observed after clonidine discontinuation, withdraw sotalol several days before the gradual withdrawal of clonidine to reduce the risk of rebound hypertension.

The common side of Sotalol includes the following

Cold hands or feet, Eye irritation, upset stomach, headache, depression, dizziness, nausea, etc.

The use of Sotalol should be prudent in the following group of special populations:

• Patients with Renal Impairment: Sotalol is excreted mainly through the kidneys. Therefore dose adjustment is required if the eGFR is less than 60 ml/min. The recommended initial dose of sotalol is 80 mg given twice daily if GFR is more than 60 ml/min, with the dose increased (generally allowing 2 to 3 days between dosing increments), up to 320 mg, given in 2 or 3 divided doses. Sotalol should be prescribed once daily if the creatinine clearance is between 40 to 60 ml/min. Data suggest that the patient population with heart failure also needs a dose adjustment. The most effective dosage for preventing atrial fibrillation is 120 mg twice daily, depending on renal function.

• Patients with Hepatic Impairment: There is no alteration in the clearance of sotalol in patients with hepatic impairment.

• Pregnancy Considerations: Half-life decreases to 10 hours in pregnancy due to the increased glomerular filtration rate. Data show that sotalol should be avoided in pregnancy. Sotalol can be teratogenic and hence, is not often the first choice in pregnant females. Close fetal monitoring is necessary when used.

• Breastfeeding Considerations: Sotalol is extensively excreted into breastmilk and has minimal safety data in breastfed infants. Other drugs are preferred to sotalol, especially while nursing a newborn or preterm infant.

Overdosage with sotalol may be fatal.

Symptoms and Treatment of Overdosage:

The most common signs to be expected are bradycardia, congestive heart failure, hypotension, bronchospasm, and hypoglycemia. In cases of massive intentional overdosage (2-16 grams) of sotalol, the following clinical findings were seen: hypotension, bradycardia, cardiac asystole, prolongation of QT interval, Torsade de Pointes, ventricular tachycardia, and premature ventricular complexes. If overdosage occurs, therapy with sotalol should be discontinued and the patient observed closely. Because of the lack of protein binding, hemodialysis is useful for reducing sotalol plasma concentrations. Patients should be carefully observed until QT intervals are normalized and the heart rate returns to levels >50 bpm. The occurrence of hypotension following an overdose may be associated with an initial slow drug elimination phase (half-life of 30 hours) thought to be due to a temporary reduction of renal function caused by the hypotension. In addition, if required, the following therapeutic measures are suggested:

• Bradycardia or Cardiac Asystole: Atropine, another anticholinergic drug, a beta-adrenergic agonist or transvenous cardiac pacing.
• Heart Block: (second and third degree) transvenous cardiac pacemaker.
• Hypotension: (depending on associated factors) epinephrine rather than isoproterenol or norepinephrine may be useful.
• Bronchospasm: Aminophylline or aerosol beta-2-receptor stimulant. Higher than normal doses of beta-2 stimulus may be required.
• Torsade de Pointes: DC cardioversion, magnesium sulfate, potassium replacement. Once Torsade de Pointes is terminated, transvenous cardiac pacing or an isoproterenol infusion to increase heart rate can be employed.

Pharmacodynamics:

• Electrophysiology:

Sotalol prolongs the plateau phase of the cardiac action potential in the isolated myocyte, as well as in isolated tissue preparations of ventricular or atrial muscle (Class III activity). In intact animals, it slows heart rate, decreases AV nodal conduction, and increases the refractory periods of atrial and ventricular muscle and conduction tissue.

• Hemodynamics:

In a study of systemic hemodynamic function measured invasively in 12 patients with a mean LV ejection fraction of 37% and ventricular tachycardia (9 sustained and 3 non-sustained), a median dose of 160 mg twice daily of sotalol produced a 28% reduction in heart rate and a 24% decrease in the cardiac index at 2 hours post-dosing at steady-state. Concurrently, systemic vascular resistance and stroke volume showed non-significant increases of 25% and 8%, respectively.

Pulmonary capillary wedge pressure increased significantly from 6 to 12 mmHg in the 11 patients who completed the study. Mean arterial pressure, mean pulmonary artery pressure and stroke work index did not significantly change. Exercise and isoproterenol-induced tachycardia are antagonized by sotalol, and total peripheral resistance increases by a small amount. In hypertensive patients, sotalol produces significant reductions in both systolic and diastolic blood pressures. Although sotalol is usually well-tolerated hemodynamically, in patients with marginal cardiac compensation, deterioration in cardiac performance may occur.

Pharmacokinetics:

• Absorption:

In healthy subjects, the oral bioavailability of sotalol is >90%. After oral administration, peak plasma concentrations are reached in 2.5 to 4 hours, and steady-state plasma concentrations are attained within 2-3 days (i.e., after 5-6 doses when administered twice daily). Over the oral dosage range of 160-640 mg/day, sotalol displays dose proportionality with respect to plasma concentrations. When administered with a standard meal, the absorption of sotalol was reduced by approximately 20% compared to administration in the fasting state.

• Distribution:

Distribution occurs to a central (plasma) and to a peripheral compartment, with a mean elimination half-life of 12 hours. Dosing every 12 hours results in trough plasma concentrations which are approximately one-half of those at peak. Sotalol does not bind to plasma proteins and is not metabolized. Sotalol shows very little intersubject variability in plasma levels. Sotalol crosses the blood-brain barrier poorly.

• Metabolism:

Sotalol is not metabolized and is not expected to inhibit or induce any CYP 450 enzymes.

• Excretion:

Excretion is predominantly via the kidney in the unchanged form, and therefore lower doses are necessary for conditions of renal impairment. Dosing every 12 hours results in trough plasma concentration which is approximately one-half of that at peak concentration.

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