Atenolol

Atenolol is a medication that belongs to the class of beta-adrenoblockers. It is used to treat various cardiovascular conditions, including hypertension (high blood pressure), angina (chest pain), and to manage certain types of arrhythmias (heart rhythm disorders).

Atenolol blocks beta-1 adrenergic receptors in the heart, resulting in the following effects:

• Reducing heart rate: Atenolol reduces stimulation of the heart, which helps reduce heart rate.
• Lowering blood pressure: By reducing the strength and rate of heartbeat, atenolol helps lower blood pressure.
• Reducing the heart's need for oxygen: This is particularly useful for treating angina pectoris as it reduces the risk of chest pain.

Indications Atenolol

1. Hypertension (arterial hypertension): Atenolol is used to lower blood pressure in patients with high blood pressure.
2. Angina: This condition is characterized by pain or discomfort in the chest area caused by inadequate blood supply to the heart muscle. Atenolol may help reduce the frequency and strength of anginal attacks.
3. Heart failure: Atenolol may be used as an adjunctive medication to improve heart function and reduce symptoms of heart failure.
4. Prophylaxis of myocardial infarction: In patients at high risk of myocardial infarction or after a previous infarction atenolol may be used for the prevention of recurrent cardiovascular complications.
5. Tachycardia: Atenolol may be used to reduce heart rate when the heart rate is accelerated.
6. Migraine prophylaxis: In some patients atenolol may be used as a prophylactic agent to reduce the frequency and severity of migraine attacks.

Release form

1. Oral tablets:

   • The most common form of release.
   • Tablets usually contain 25 mg, 50 mg, or 100 mg of atenolol.
   • Tablets can be either regular-acting or prolonged-acting (long-acting).

2. Coated tablets:

   • Coated tablets help prevent stomach irritation and provide a more sustained release of the active ingredient in the body.

Pharmacodynamics

1. Selectivity to beta-1 adrenoreceptors:

   • Atenolol is a selective beta-1 adrenoreceptor blocker. This means that it preferentially blocks beta-1 receptors, which are predominantly located in the heart.
   • Blocking beta-1 adrenoreceptors reduces stimulation of the heart muscle, resulting in a decrease in heart rate and the force of heart contraction.

2. Reduced cardiac workload:

   • Blocking beta-1 adrenoreceptors leads to a decrease in the heart's oxygen and energy requirements by lowering cardiac output and blood pressure.
   • It is particularly useful in the treatment of hypertension and coronary heart disease because it reduces the strain on the heart.

3. Decreased pressure in the arteries:

   • Atenolol lowers blood pressure by decreasing the minute volume of the heart and reducing peripheral vascular resistance.
   • This mechanism helps control blood pressure and reduces the risk of cardiovascular complications.

4. Prolonged effect:

   • Atenolol has a long-lasting effect, which allows it to be used in forms with a single daily dose.

5. Antiarrhythmic action:

   • Blocking beta-1 adrenoreceptors may prevent arrhythmias by reducing heart automaticity and conduction in the heart.

Pharmacokinetics

Absorption

• Bioavailability: Atenolol has a relatively low oral bioavailability of about 40-50%, which is due to its poor lipophilicity and low permeability across lipid membranes.
• Thetime to reach maximum plasma concentration after oral administration is approximately 2-4 hours.

Distribution

• Thevolume of distribution of atenolol is relatively small, indicating its limited distribution outside the vascular bed. This is explained by its hydrophilicity.
• Atenolol penetrates the blood-brain barrier poorly, making its central nervous side effects less severe than some other beta-blockers.

Metabolism

• Atenolol is metabolized to a very small extent and is mostly excreted unchanged.
• This makes atenolol more predictable than beta-blockers, which are extensively metabolized in the liver, especially in the setting of concomitant liver disease.

Excretion

• Kidneys are the main route of atenolol excretion, about 85-100% of the dose is excreted by kidneys in unchanged form. This makes it necessary to adjust the dose in case of renal dysfunction.
• Theelimination half-life of atenolol is approximately 6-7 hours in healthy subjects, but may increase with decreased renal function.

Dosing and administration

Method of application

• Atenolol is taken orally, usually once a day.
• The tablets should be swallowed whole, without chewing or crushing, with enough water. It can be taken with or without food, but it is best to take the medicine at the same time each day to maintain an even level of the medicine in the blood.

Dosage

For adults

• Hypertension: The starting dose is usually 50 mg once daily. Depending on the response to treatment, the dose may be increased to 100 mg once daily.
• Angina pectoris: The standard dose is 50-100 mg once daily.
• Migraine prevention and treatment of heart flutter: Dosage may vary, but usually starts at 50 mg once daily.

For elderly patients

• A dose reduction may be required depending on renal function and general health.

For children

• The use of atenolol in children should be strictly controlled by a doctor, and the dosage will depend on the specific case and the child's condition.

Special Instructions

• Blood pressure and heart rate should be monitored regularly to assess the efficacy and safety of treatment.
• Atenolol should not be stopped abruptly, as this may lead to a worsening of the condition. Any changes in the regimen should be discussed with your doctor.
• Patients with asthma or other bronchial diseases should take atenolol with extreme caution because beta-blockers can cause bronchospasm.

Use Atenolol during pregnancy

Atenolol use during pregnancy may be contraindicated due to potential risk to fetal health. Atenolol belongs to the group of beta-blockers and may have a negative effect on fetal development, especially with prolonged and/or excessive use.

Contraindications

1. Bradycardia:

   • Atenolol may cause further slowing of the heart rate, which is dangerous in patients with pre-existing bradycardia (slow heartbeat).

2. AV block of II or III degree (without an installed pacemaker):

   • Atenolol may increase blockade, resulting in significant impairment of cardiac conduction.

3. Decompensated heart failure:

   • The use of atenolol may worsen the condition of patients with unstable or decompensated heart failure, as beta-blockers reduce the strength and rate of heart contractions.

4. Shock, including cardiogenic shock:

   • In states of shock, where maintenance of heart rate strength is important, the use of atenolol may be counterproductive.

5. Severe bronchial asthma or chronic obstructive pulmonary disease (COPD):

   • Atenolol can cause bronchoconstriction (narrowing of the airways), which is especially dangerous for patients with lung disease.

6. Severe forms of peripheral arterial disease:

   • Atenolol can worsen symptoms such as leg pain and coldness of the extremities due to decreased blood flow.

7. Metabolic acidosis:

   • A condition in which acid levels are elevated in the blood may be aggravated by the use of atenolol.

8. Hypotension (low blood pressure):

   • The use of atenolol may additionally lower blood pressure, which is dangerous for hypotensive patients.

9. Diabetes mellitus:

   • Atenolol can mask symptoms of hypoglycemia (low blood sugar), which is especially important to consider in diabetics.

Side effects Atenolol

1. Drowsiness and fatigue: Many patients may experience drowsiness, fatigue, or general weakness while taking atenolol.
2. Cold extremities: Some people may experience a cold sensation in the hands and feet due to constriction of blood vessels.
3. Dry throat or nose: Dry throat or nose may occur.
4. Decreased sexual desire: Dec reased sexual desire or erectile dysfunction may occur in some patients while taking atenolol.
5. Bradycardia: This is a condition in which the heart rate drops to lower values, which can cause feelings of fatigue or dizziness.
6. Headache: Some patients may experience headaches or dizziness.
7. Nonspecific complaints: These include vague symptoms such as nausea, abdominal pain, or general malaise.
8. Decrease in blood pressure: When using atenolol, a decrease in blood pressure may occur, which may lead to dizziness or a feeling of weakness.
9. Specific side effects: Include bronchospasm (worsening of respiratory function in asthmatics), masking hypoglycemia (masking symptoms of low blood sugar in diabetic patients), increased reaction to allergens, and others.

Overdose

1. Cardiovascular complications:

   • One of the main effects of atenolol overdose is a decrease in heart rate and blood pressure to dangerous levels.
   • This can lead to serious circulatory problems, including hypotension, bradycardia, and even shock.

2. Central nervous system (CNS) depression:

   • Atenolol overdose can cause drowsiness, fainting, dizziness, decreased response to external stimuli, and even coma.
   • This is due to its ability to depress the activity of the central nervous system.

3. Respiratory Disturbances:

   • Excessive central nervous system depression can also lead to decreased respiratory rate and even respiratory arrest.

4. Metabolic disorders:

   • Atenolol overdose can cause metabolic disturbances such as hyperglycemia (increased blood sugar) and hypokalemia (decreased blood potassium).

5. Other unwanted effects:

   • Other possible effects of atenolol overdose include cold extremities, sweating, weight gain, and decreased potency.

Interactions with other drugs

1. Other antihypertensive drugs: The use of atenolol with other antihypertensive drugs such as diuretics, angiotensin-converting enzyme inhibitors (ACEIs) or calcium antagonists may result in an increased hypotensive effect and an increased risk of hypotensive reactions such as dizziness and syncope.
2. Sympathomimetics: Co-administration of atenolol with sympathomimetics such as adrenaline or albuterol may reduce their efficacy due to blocking of beta-adrenoreceptors.
3. Heart rhythm depressant drugs: Atenolol may increase the depressive effect on heart rate of other drugs, such as amidarone or digoxin, which may result in decreased heart rate and increased antiarrhythmic effects.
4. Antidepressants and anxiolytics: Atenolol may increase the sedative effect of drugs such as benzodiazepines and tricyclic antidepressants, which may lead to increased drowsiness and decreased psychomotor activity.
5. Insulin and hypoglycemic drugs: Atenolol may mask the symptoms of hypoglycemia and reduce its occurrence, which may delay the diagnosis of hypoglycemic states in patients with diabetes mellitus.