General
Candesartan Cilexetil-Hydrochlorothiazide
In clinical trials of various doses of candesartan cilexetil and hydrochlorothiazide, the incidence of hypertensive patients who developed hypokalemia (serum potassium < 3.5 mEq/L) was 2.5% versus 2.1% for placebo; the incidence of hyperkalemia (serum potassium > 5.7 mEq/L) was 0.4% versus 1.0% for placebo. No patient receiving ATACAND HCT 16-12.5 mg or 32-12.5 mg was discontinued due to increases or decreases in serum potassium. Overall, the combination of candesartan cilexetil and hydrochlorothiazide had no clinically significant effect on serum potassium.
Candesartan
Major Surgery/Anesthesia- Hypotension may occur during major
surgery and anesthesia in patients treated with angiotensin II receptor antagonists,
including candesartan, due to blockade of the renin-angiotensin system. Very
rarely, hypotension may be severe such that it may warrant the use of intravenous
fluids and/or vasopressors.
Hydrochlorothiazide
Periodic determination of serum electrolytes to detect possible electrolyte imbalance should be performed at appropriate intervals.
All patients receiving thiazide therapy should be observed for clinical signs of fluid or electrolyte imbalance: namely, hyponatremia, hypochloremic alkalosis, and hypokalemia. Serum and urine electrolyte determinations are particularly important when the patient is vomiting excessively or receiving parenteral fluids. Warning signs or symptoms of fluid and electrolyte imbalance, irrespective of cause, include dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, confusion, seizures, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal disturbances such as nausea and vomiting.
Hypokalemia may develop, especially with brisk diuresis, when severe cirrhosis is present, or after prolonged therapy. Interference with adequate oral electrolyte intake will also contribute to hypokalemia. Hypokalemia may cause cardiac arrhythmia and may also sensitize or exaggerate the response of the heart to the toxic effects of digitalis (eg, increased ventricular irritability).
Although any chloride deficit is generally mild and usually does not require specific treatment, except under extraordinary circumstances (as in liver disease or renal disease), chloride replacement may be required in the treatment of metabolic alkalosis.
Dilutional hyponatremia may occur in edematous patients in hot weather; appropriate therapy is water restriction, rather than administration of salt, except in rare instances when the hyponatremia is life-threatening. In actual salt depletion, appropriate replacement is the therapy of choice.
Hyperuricemia may occur or acute gout may be precipitated in certain patients receiving thiazide therapy.
In diabetic patients dosage adjustments of insulin or oral hypoglycemic agents may be required. Hyperglycemia may occur with thiazide diuretics. Thus latent diabetes mellitus may become manifest during thiazide therapy.
The antihypertensive effects of the drug may be enhanced in the post-sympathectomy patient.
If progressive renal impairment becomes evident consider withholding or discontinuing diuretic therapy.
Thiazides have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia.
Thiazides may decrease urinary calcium excretion. Thiazides may cause intermittent and slight elevation of serum calcium in the absence of known disorders of calcium metabolism. Marked hypercalcemia may be evidence of hidden hyperparathyroidism. Thiazides should be discontinued before carrying out tests for parathyroid function.
Increases in cholesterol and triglyceride levels may be associated with thiazide diuretic therapy.
Impaired Renal Function
Candesartan Cilexetil
As a consequence of inhibiting the renin-angiotensin-aldosterone system, changes
in renal function may be anticipated in susceptible individuals treated with
candesartan cilexetil. In patients whose renal function may depend upon the
activity of the renin-angiotensin-aldosterone system (eg, patients with severe
congestive heart failure), treatment with angiotensin-converting enzyme inhibitors
and angiotensin receptor antagonists has been associated with oliguria and/or
progressive azotemia and (rarely) with acute renal failure and/or death. Similar
results may be anticipated in patients treated with candesartan cilexetil. (See
CLINICAL PHARMACOLOGY, Special Populations.)
In studies of ACE inhibitors in patients with unilateral or bilateral renal artery stenosis, increases in serum creatinine or blood urea nitrogen (BUN) have been reported. There has been no long-term use of candesartan cilexetil in patients with unilateral or bilateral renal artery stenosis, but similar results may be expected.
Hydrochlorothiazide
Thiazides should be used with caution in severe renal disease. In patients with renal disease, thiazides may precipitate azotemia. Cumulative effects of the drug may develop in patients with impaired renal function.
Impaired Hepatic Function
Candesartan Cilexetil
Based on pharmacokinetic data significant increases in candesartan AUC and
Cmax in patients with moderate hepatic impairment have been demonstrated. (See
CLINICAL PHARMACOLOGY, Special Populations.)
Carcinogenesis, Mutagenesis, Impairment of Fertility
No carcinogenicity studies have been conducted with the combination of candesartan cilexetil and hydrochlorothiazide. There was no evidence of carcinogenicity when candesartan cilexetil was orally administered to mice and rats for up to 104 weeks at doses up to 100 and 1000 mg/kg/day, respectively. Rats received the drug by gavage whereas mice received the drug by dietary administration. These (maximally-tolerated) doses of candesartan cilexetil provided systemic exposures to candesartan (AUCs) that were, in mice, approximately 7 times and, in rats, more than 70 times the exposure in man at the maximum recommended daily human dose (32 mg). Two-year feeding studies in mice and rats conducted under the auspices of the National Toxicology Program (NTP) uncovered no evidence of a carcinogenic potential of hydrochlorothiazide in female mice (at doses of up to approximately 600 mg/kg/day) or in male and female rats (at doses of up to approximately 100 mg/kg/day). The NTP, however, found equivocal evidence for hepatocarcinogenicity in male mice.
Candesartan cilexetil or candesartan (the active metabolite), in combination
with hydrochlorothiazide, tested positive in vitro in the Chinese hamster
lung (CHL) chromosomal aberration assay and mouse lymphoma mutagenicity assay.
The candesartan cilexetil/hydrochlorothiazide combination tested negative for
mutagenicity in bacteria (Ames test), for unscheduled DNA synthesis in rat liver,
for chromosomal aberrations in rat bone marrow and for micronuclei in mouse
bone marrow.
Both candesartan and its O-deethyl metabolite tested positive for genotoxicity
in the in vitro CHL chromosomal aberration assay. Neither compound tested
positive in the Ames microbial mutagenesis assay or in the in vitro mouse
lymphoma cell assay. Candesartan (but not its O-deethyl metabolite) was also
evaluated in vivo in the mouse micronucleus test and in vitro
in the Chinese hamster ovary (CHO) gene mutation assay, in both cases with negative
results. Candesartan cilexetil was evaluated in the Ames test, the in vitro
mouse lymphoma cell assay, the in vivo rat hepatocyte unscheduled DNA
synthesis assay and the in vivo mouse micronucleus test, in each case
with negative results. Candesartan cilexetil was not evaluated in the CHL chromosomal
aberration or CHO gene mutation assays.
When hydrochlorothiazide was tested alone, positive results were obtained in
vitro in the CHO sister chromatid exchange (clastogenicity) and mouse lymphoma
cell (mutagenicity) assays and in the Aspergillus nidulans non-disjunction assay.
Hydrochorothiazide was not genotoxic in vitro in the Ames test for point
mutations and the CHO test for chromosomal aberrations, or in vivo in
assays using mouse germinal cell chromosomes, Chinese hamster bone marrow chromosomes,
and the Drosophila sex-linked recessive lethal trait gene.
No fertility studies have been conducted with the combination of candesartan cilexetil and hydrochlorothiazide. Fertility and reproductive performance were not affected in studies with male and female rats given oral doses of up to 300 mg candesartan cilexetil/kg/day (83 times the maximum daily human dose of 32 mg on a body surface area basis). Hydrochlorothiazide had no adverse effects on the fertility of mice and rats of either sex in studies wherein these species were exposed, via their diet, to doses of up to 100 and 4 mg/kg, respectively, prior to conception and throughout gestation.
Pregnancy
Pregnancy Categories C (first trimester) and D
(second and third trimesters)
See WARNINGS, Fetal/Neonatal Morbidity and Mortality.
Nursing Mothers
It is not known whether candesartan is excreted in human milk, but candesartan has been shown to be present in rat milk. Thiazides appear in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established.
Geriatric Use
Of the total number of subjects in all clinical studies of ATACAND HCT (2831), 611 (22%) were 65 and over, while 94 (3%) were 75 and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
Hydrochlorothiazide is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function.
Last updated on RxList: 7/14/2008