Betaxolol

(be TAX oh lohl)

Introduced: 1983

Class: Antihypertensive, beta-adrenergic blocker

Prescription: USA: Yes

Controlled Drug: USA: No

Available as Generic: No Brand Names: Betoptic, Kerlone

Principal Uses

As a Single Drug Product: Used primarily to treat (1) mild to moderately severe high blood pressure; (2) chronic open-angle glaucoma (eye drops). May be used alone or concurrently with other antihypertensive drugs, such as diuretics.

How This Drug Works: By blocking certain actions of the sympathetic nervous system, this drug

• reduces the rate and contraction force of the heart, thus lowering the ejection pressure of the blood leaving the heart and reducing the oxygen requirement for heart function.

• reduces the degree of contraction of blood vessel walls, resulting in their relaxation and expansion and consequent lowering of blood pressure.

• reduces the internal pressure of the eye.

Available Dosage Forms and Strengths

Eye drops — 0.5%

Tablets — 10 mg, 20 mg

Usual Adult Dosage Range: Initially 10 mg once daily. Dose may be in­creased gradually at intervals of 7 to 14 days as needed and tolerated up to 20 mg/24 hours. The usual maintenance dose is 10 to 15 mg/24 hours. The total dose should not exceed 20 mg/24 hours. Note: Actual dosage and administration schedule must be determined by the physician for each patient individually.

Dosing Instructions: May be taken without regard to eating. The tablet may be crushed for administration. Do not discontinue this drug abruptly.

Usual Duration of Use: Continual use on a regular schedule for 10 to 14 days is usually necessary to determine this drug's effectiveness in low­ering blood pressure. The long-term use of this drug will be determined by the course of your blood pressure over time and your response to the overall treatment program (weight reduction, salt restriction, smoking cessation, etc.) Consult your physician on a regular basis.

Possible Advantages of This Drug: Usually effective and well tolerated with a single dose daily.

Currently a "Drug of Choice"

for initiating treatment of hypertension with a single drug, especially for those subject to bronchial asthma or diabetes.

This Drug Should Not Be Taken If

• you have had an allergic reaction to it previously.

• you have congestive heart failure.

• you have an abnormally slow heart rate or a serious form of heart block.

• you are taking, or have taken within the past 14 days, any monoamine oxidase (MAO) type A inhibitor drug.

Inform Your Physician Before Taking This Drug If

• you have had an adverse reaction to any beta blocker drug in the past.

• you have a history of serious heart disease, with or without episodes of heart failure.

• you have a history of hay fever (allergic rhinitis), asthma, chronic bronchitis or emphysema.

• you have a history of overactive thyroid function (hyperthyroidism).

• you have a history of low blood sugar (hypoglycemia).

• you have impaired liver or kidney function.

• you have diabetes or myasthenia gravis.

• you are currently taking any form of digitalis, quinidine or reserpine, or any calcium blocker drug.,

• you plan to have surgery under general anesthesia in the near future.

Possible Side-Effects (natural, expected and unavoidable drug actions) Lethargy (2.8%), fatigability (2.9%), cold extremities (1.9%), slow heart rate (8.1%), light-headedness in upright position (see Orthostatic Hypo­tension in Glossary).

Possible Adverse Effects (unusual, unexpected and infrequent reactions) If any of the following develop, consult your physician promptly for guidance.

Mild Adverse Effects

Allergic Reactions: Skin rash (1.2%), itching.

Headache (6.5%), dizziness (4.5%), drowsiness, insomnia (1.2%), abnormal dreams (1.0%).

Indigestion (4.7%), nausea (1.6%), diarrhea (2.0%).

Joint and muscle discomfort (3.1%), fluid retention (edema) (1.8%). Serious Adverse Effects

Mental depression (0.8%), anxiety (0.8%).

Chest pain (2.4%), shortness of breath (2.4%), precipitation of congestive heart failure.

Induction of bronchial asthma (in asthmatic individuals).

Possible Effects on Sexual Function: Decreased libido, impotence (1.2%). Altered menstrual patterns.

Adverse Effects That May Mimic Natural Diseases or Disorders

Reduced blood flow to extremities may resemble Raynaud's phenome­non (see Glossary).

Possible Effects on Laboratory Tests

Glaucoma-screening test (measurement of internal eye pressure): pres­sure is decreased (false low or normal value). Antinuclear antibodies (ANA) test: positive in 5.3% of users. Blood platelet counts: decreased (rarely).

CAUTION

1. Do not discontinue this drug suddenly without the knowledge and guidance of your physician. Carry a notation on your person that you are taking this drug.

2. Consult your physician or pharmacist before using nasal deconges­ tants usually present in over-the-counter cold preparations and nose drops. These can cause sudden increases in blood pressure when taken concurrently with beta blocker drugs.

3. Report the development of any tendency to emotional depression.

Precautions for Use

By Infants and Children: Safety and effectiveness for use by those under 12 years of age have not been established. However, if this drug is used, observe for the development of low blood sugar (hypoglycemia) during periods of reduced food intake.

By Those over 60 Years of Age: Proceed cautiously with all antihypertensive drugs. Unacceptably high blood pressure should be reduced without creating the risks associated with excessively low blood pressure. Start treatment with 5 mg daily and monitor the blood pressure response frequently. Sudden, rapid and excessive reduction of blood pressure can predispose to stroke or heart attack. Total daily dosage should not exceed 10 to 15 mg. Observe for dizziness, unsteadiness, tendency to fall, confusion, hallucinations, depression or urinary frequency. This age group is more prone to develop excessively slow heart rates and hypothermia.

Advisability of Use During Pregnancy

Pregnancy Category: C (tentative). See Pregnancy Code inside back cover.

Animal studies: Rat studies reveal increased resorptions of embryo and fetus, retarded growth and development of newborn and mild skeletal defects.

Human studies: Information from adequate studies of pregnant women is not available.

Avoid use of drug during the first 3 months if possible. Avoid use during labor and delivery because of the possible effects on the newborn infant.

Advisability of Use if Breast-Feeding

Presence of this drug in breast milk: Yes.

Avoid drug if possible. If drug is necessary, observe nursing infant for slow heart rate and indications of low blood sugar.

Habit-Forming Potential: None.

Effects of Overdosage: Weakness, slow pulse, low blood pressure, fainting, cold and sweaty skin, congestive heart failure, possible coma and con­vulsions.

Possible Effects of Long-Term Use: Reduced heart reserve and eventual heart failure in susceptible individuals with advanced heart disease.

Suggested Periodic Examinations While Taking This Drug (at physician's

discretion) Measurements of blood pressure, evaluation of heart function.

While Taking This Drug, Observe the Following

Foods: No restrictions. Avoid excessive salt intake.

Beverages: No restrictions. May be taken with milk.

Alcohol: Use with caution until the combined effect has been determined.

Alcohol may exaggerate this drug's ability to lower blood pressure and

may increase its mild sedative effect. Tobacco Smoking: Nicotine may reduce this drug's effectiveness in treating

high blood pressure. In addition, high doses of this drug may potentiate

the constriction of the bronchial tubes caused by regular smoking. Other Drugs Betaxolol may increase the effects of

• other antihypertensive drugs and cause excessive lowering of blood pressure. Dosage adjustments may be necessary.

• reserpine (Ser-Ap-Es, etc.) and cause sedation, depression, slowing of heart rate and lowering of blood pressure (light-headedness, fainting).

Betaxolol taken concurrently with

• clonidine (Catapres) requires close monitoring for rebound high blood pressure if clonidine is withdrawn while betaxolol is still being taken.

• insulin requires close monitoring to avoid undetected hypoglycemia.

The following drugs may decrease the effects of betaxolol:

indomethacin (Indocin), and possibly other "aspirin substitutes," may impair betaxolol's antihypertensive effect.

Driving, Hazardous Activities: Use caution until the full extent of drowsi­ness, lethargy, and blood pressure change has been determined.

Aviation Note: The use of this drug is a disqualification for piloting. Consult a designated Aviation Medical Examiner.

Exposure to Sun: No restrictions.

Exposure to Heat: Caution advised. Hot environments can lower blood pressure and exaggerate the effects of this drug.

Exposure to Cold: Caution advised. Cold environments can enhance the circulatory deficiency in the extremities that may occur with this drug. The elderly should take precautions to prevent hypothermia (see Glossary).

Heavy Exercise or Exertion: It is advisable to avoid exertion that produces light-headedness, excessive fatigue, or muscle cramping. The use of this drug may intensify the hypertensive response to isometric exercise.

Occurrence of Unrelated Illness: The fever that accompanies systemic infec­tions can lower blood pressure and require adjustment of dosage. Ill­nesses that cause nausea or vomiting may interrupt the regular dosage schedule. Ask your physician for guidance.

Discontinuation: It is advisable to avoid sudden discontinuation of this drug in all situations. If possible, gradual reduction of dose over a period of 2 to 3 weeks is recommended. Ask your physician for specific guidance.

TEXT 13. Read the following text and translate it into Ukrainian using a dictionary.