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TENORETIC (atenolol and chlorthalidone) is usually well tolerated in properly selected patients. Most adverse effects have been mild and transient.The adverse effects observed for TENORETIC (atenolol and chlorthalidone) are essentially the same as those seen with the individual components.


The frequency estimates in the following table were derived from controlled studies in which adverse reactions were either volunteered by the patient (US studies) or elicited, eg, by checklist (foreign studies). The reported frequency of elicited adverse effects was higher for both atenolol and placebo treated patients than when these reactions were volunteered. Where frequency of adverse effects for atenolol and placebo is similar, causal relationship to atenolol is uncertain.

  Volunteered (US Studies) Total-Volunteered and Elicited (Foreign + US Studies)
(n = 164)
(n = 206)
(n = 399)
(n = 407)
Bradycardia 3 0 3 0
Cold Extremities 0 0.5 12 5
Postural Hypotension 2 1 4 5
Leg Pain 0 0.5 3 1
Dizziness 4 1 13 6
Vertigo 2 0.5 2 0.2
Light-Headedness 1 0 3 0.7
Tiredness 0.6 0.5 26 13
Fatigue 3 1 6 5
Lethargy 1 0 3 0.7
Drowsiness 0.6 0 2 0.5
Depression 0.6 0.5 12 9
Dreaming 0 0 3 1
Diarrhea 2 0 3 2
Nausea 4 1 3 1
Wheeziness 0 0 3 3
Dyspnea 0.6 1 6 4

During postmarketing experience, the following have been reported in temporal relationship to the use of the drug: elevated liver enzymes and/or bilirubin, hallucinations, headache, impotence, Peyronie's disease, postural hypotension which may be associated with syncope, psoriasiform rash or exacerbation of psoriasis, psychoses, purpura, reversible alopecia, thrombocytopenia, visual disturbance, sick sinus syndrome, and dry mouth. TENORETIC (atenolol and chlorthalidone) , like other beta blockers, has been associated with the development of antinuclear antibodies (ANA), lupus syndrome, and Raynaud's


Cardiovascular: orthostatic hypotension; Gastrointestinal: anorexia, gastric irritation, vomiting, cramping, constipation, jaundice (intrahepatic cholestatic jaundice), pancreatitis; CNS: vertigo, paresthesia, xanthopsia; Hematologic: leukopenia, agranulocytosis, thrombocytopenia, aplastic anemia; Hypersensitivity: purpura, photosensitivity, rash, urticaria, necrotizing angiitis (vasculitis) (cutaneous vasculitis), Lyell's syndrome (toxic epidermal necrolysis); Miscellaneous: hyperglycemia, glycosuria, hyperuricemia, muscle spasm, weakness, restlessness. Clinical trials of TENORETIC (atenolol and chlorthalidone) conducted in the United States (89 patients treated with TENORETIC (atenolol and chlorthalidone) ) revealed no new or unexpected adverse effects.

Potential Adverse Effects

In addition, a variety of adverse effects not observed in clinical trials with atenolol but reported with other beta-adrenergic blocking agents should be considered potential adverse effects of atenolol. Nervous System: Reversible mental depression progressing to catatonia; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability, slightly clouded sensorium, decreased performance on neuropsychometrics; Cardiovascular: Intensification of AV block (see CONTRAINDICATIONS); Gastrointestinal: Mesenteric arterial thrombosis, ischemic colitis; Hematologic: Agranulocytosis; Allergic: Erythematous rash, fevercombined with aching and sore throat, laryngospasm and respiratory distress.


There have been reports of skin rashes and/or dry eyes associated with the use of beta-adrenergic blocking drugs. The reported incidence is small, and, in most cases, the symptoms have cleared when treatment was withdrawn. Discontinuance of the drug should be considered if any such reaction is not otherwise explicable. Patients should be closely monitored following cessation of therapy. (See DOSAGE AND ADMINISTRATION.)

The oculomucocutaneous syndrome associated with the beta blocker practolol has not been reported with atenolol (TENORMIN). Furthermore, a number of patients who had previously demonstrated established practolol reactions were transferred to atenolol (TENORMIN) therapy with subsequent resolution or quiescence of the reaction.

Clinical Laboratory Test Findings

Clinically important changes in standard laboratory parameters were rarely associated with the administration of TENORETIC (atenolol and chlorthalidone) . The changes in laboratory parameters were notprogressive and usually were not associated with clinical manifestations. The most common changes were increases inuric acid and decreases in serum potassium.