Dosing & Uses
Dosage Forms & Strengths
atenolol/chlorthalidone
tablet
- 50mg/25mg
- 100mg/25mg
Hypertension
Not indicated for initial therapy
If the fixed dose combination represents the dose appropriate to the individual patient's needs, it may be more convenient than the separate components
Initial dose: 50 mg atenolol/25 mg chlorthalidone PO qDay
May increase to 100 mg atenolol/25 mg chlorthalidone PO qDay if needed
When necessary, another antihypertensive agent may be added gradually beginning with 50 percent of the usual recommended starting dose to avoid an excessive fall in blood pressure
Renal Impairment
Use caution in dosing/titrating patients with renal dysfunction
Cumulative effects of thiazides may develop with impaired renal function
CrCl > 35 mL/min/1.73 m²: Dose adjustment not necessary
CrCl 15-35 mL/min/1.73 m²: Maximum 50 mg PO qDay
CrCl <15 mL/min/1.73 m²: Maximum 25 mg PO qDay or 50 mg PO every other day
Anuria: Contraindicated
Hepatic Impairment
Not studied; use caution
Administration
Combination may be substituted for the titrated individual components
Withdraw gradually over a period of about 2 weeks
May need dosage reduction for geriatric patients
<18 years: Safety/efficacy not established
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
No adverse effects specific to the combination have been observed; adverse effects limited to those previously reported with atenolol and chlorthalidone
Frequency Not Defined
Atenolol
- 2/3° AV block
- Bradycardia
- Cold extremities
- Diarrhea
- Drowsiness
- Hypotension
- Leg pain
- Lethargy
- Lightheadedness
- Nausea
- Postural hypotension
- Unusual dreams
- Vertigo
Chlorthalidone
- Blurred vision, xanthopsia
- Constipation
- Diarrhea
- Dizziness
- Electrolyte abnormalities
- Headache, vasculitis
- Hyperglycemia
- Hyperuricemia
- Hypotension
- Impotence
- Loss of appetite
- Muscular spasticity, restlessness
- Nausea/vomiting
- Paresthesia
- Photosensitivity, phototoxicity
< 1%
Atenolol
- Antinuclear antibodies (ANA), catatonia, disorientation, elevated serum hepatic enzymes & bilirubin, emotional lability, fatigue, hallucinations, headache, hypotension, impaired performance on neuropsychometric tests, impotence, lupus syndrome, mental depression, nausea, Peyronie's disease, psychoses, purpura, rashes, severe CHF, short-term memory impairment, sick sinus syndrome, thrombocytopenia, visual disturbances, wheezing & dyspnea more likely if dose >100 mg qD, xerophthalmia, xerostomia
Chlorthalidone
- Cardiac dysrhythmia (rare), disorder of hematopoietic structure (rare), hepatotoxicity (rare), pancreatitis (rare), pulmonary edema (rare), scaling eczema (ra re), stevens-Johnson syndrome (rare), systemic lupus erythematosus (rare), toxic epidermal necrolysis (rare)
Warnings
Black Box Warning
Exacerbation of angina and, in some cases, myocardial infarction reported, after abrupt discontinuation
When discontinuing chronically administered beta-blockers (particularly with ischemic heart disease) gradually reduce dose over 1-2 weeks and carefully monitor
If angina markedly worsens or acute coronary insufficiency develops, reinstate beta-blocker administration promptly, at least temporarily (in addition to other measures appropriate for unstable angina)
Warn patients against interruption or discontinuation of beta-blocker without physician advice
Contraindications
Anuria
Cardiogenic shock
Heart block 2°/3°
Hypersensitivity to either component or sulfonamides
Overt cardiac failure
Sinus bradycardia
Untreated pheochromocytoma
Cautions
Surgery/Anesthesia: Chronically administered beta-blockers should not be routinely withdrawn prior to major surgery; however, impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures
Bronchospastic disease
Cerebrovascular insufficiency
Correct hypokalemia before initiating therapy
CHF, beta blockade carries the potential hazard of further depressing myocardial contractility and precipitating more severe failure
Use caution in diabetes mellitus, fluid or electrolyte imbalance (hypochloremic alkalosis, hypercalcemia, hyponatremia), moderate or high cholesterol concentrations, history of asthma, hyperuricemia or gout, hypotension, SLE
Hyperthyroidism/thyrotoxicosis, liver disease
May aggravate digitalis toxicity
Peripheral vascular disease
Renal impairment
Risk of male sexual dysfunction
Sensitivity reactions may occur with or without history of allergy or asthma
Compromised left ventricular function
Patients receiving clonidine - discontinue atenolol several days prior to withdrawal of clonidine
Pregnancy & Lactation
Pregnancy Category: D
Lactation: excreted in breast milk, use caution
Pregnancy Categories
A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA:Information not available.
Pharmacology
Mechanism of Action
Atenolol/chlorthalidone is a fixed-combination tablet that combines a beta adrenergic receptor blocker atenolol, and a diuretic, chlorthalidone
Atenolol: Cardioselective inhibitor of beta(1)-adrenoceptor, has no significant intrinsic sympathomimetic activity or membrane stabilizing activity in its therapeutic dosage; exhibits beta(2)-adrenoceptors inhibition and negative chronotropic effect
Chlorthalidone: Monosulfonamyl diuretic inhibits Na and Cl reabsorption in cortical-diluting segment of ascending loop of Henle
Pharmacokinetics
Atenolol
- Onset: 2-4 hr (peak effect)
- Protein binding: 6-16%
- Metabolism: Liver
- Duration: 12-24 hr (normal renal function)
- Absorption: 50%
- Half-life: 6-7 hr (normal renal function); 15-35 hr (end stage renal disease); >5 hr (children >10 years of age); < 5 hr (children 5-10 year of age)
- Peak plasma time: 2-4 hr (PO)
- Excretion: Feces (50%); urine (40%)
Chlorthalidone
- Duration: 24-72 hr
- Onset: 2-6 hr (peak effect)
- Metabolism: Liver
- Protein binding: 75%
- Bioavailability: 60-65%
- Excretion: Urine (50-65%)
- Half-life: 40-60 hr (normal renal function); prolonged in renal impairment; 81 hr (anuria)
Images
Patient Handout
Formulary
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