Atenolol/chlorthalidone is a combination of atenolol (Tenormin) and chlorthalidone (Hygroton) used for the treatment of high blood pressure. Atenolol is a beta-adrenergic blocking agent that blocks the effects of adrenergic drugs, for example, adrenaline or epinephrine, on nerves of the sympathetic nervous system. Atenolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Atenolol also reduces the force of contraction of heart muscle and lowers blood pressure. Chlorthalidone is a diuretic (water pill). It works by reducing the kidneys' ability to hold on to salt and water and increasing the kidneys' production of urine (diuresis). It is used to eliminate excess salt and water from the body and to treat high blood pressure. The FDA approved atenolol/chlorthalidone in June 1984.

Tenoretic

GENERIC AVAILABLE: yes

yes

Side effects of Atenolol/chlorthalidone are similar to side effects form the individual components and are:

• Drowsiness
• Nausea
• Weakness
• Headache
• Loss of electrolytes
• Slow heart rate
• Low blood pressure
• Cold extremities
• Dizziness
• Unusual dreams
• Impotence
• Sun sensitivity

The recommended dose of atenolol/chlorthalidone is one tablet once daily starting with 50 mg/25 mg then increasing to 100 mg/25 mg if blood pressure control is not adequate.

• Chlorthalidone can lower blood potassium and magnesium levels because both potassium and magnesium are lost in the urine.
• Chlorthalidone reduces the kidney's ability to eliminate lithium (Lithobid) in the urine. As a result, patients taking chlorthalidone at the same time as drugs containing lithium may develop high levels of lithium and/or lithium toxicity.
• Atenolol can mask the early warning symptoms of low blood sugar (hypoglycemia), and should be used with caution in patients receiving treatment for diabetes. Combining atenolol with other drugs that reduce blood pressure or slow heart rate may lead to excessive blood pressure reduction or low heart rate.

Atenolol is excreted in breast milk and may adversely affect the infant. Atenolol/chlorthalidone should be avoided while breastfeeding.

What preparations of atenolol and chlorthalidone are available?

Tablets: atenolol 50mg and chlorthalidone 25mg; atenolol 100mg and chlorthalidone 25mg.

How should I keep atenolol and chlorthalidone stored?

Tablets should be stored at room temperature, 15C and 30 C (59 F and 86 F).