General
Olmesartan
medoxomil-hydrochlorothiazideIn a double-blind clinical trial of various doses of olmesartan
medoxomil and hydrochlorothiazide, the incidence of hypertensive patients who
developed hypokalemia (serum potassium <3.4 mEq/L) was 2.1%; the incidence of
hyperkalemia (serum potassium >5.7 mEq/L) was 0.4%. In this trial, no patient
discontinued due to increases or decreases in serum potassium.
HydrochlorothiazidePeriodic determinations 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: hyponatremia, hypochloremic alkalosis and hypokalemia.
Serum and urine electrolyte determinations are 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 (e.g.,
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 frank 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
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
As a consequence of inhibiting the renin-angiotensin-aldosterone
system, changes in renal function may be anticipated in susceptible individuals
treated with olmesartan medoxomil. In patients whose renal function may depend
upon the activity of the renin-angiotensin-aldosterone system (e.g. 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
olmesartan medoxomil. (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 olmesartan medoxomil in
patients with unilateral or bilateral renal artery stenosis, but similar results
may be expected.
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.
Information for Patients
Pregnancy:Female patients of
childbearing age should be told about the consequences of second and third
trimester exposure to drugs that act on the renin-angiotensin system and they
should be told also that these consequences do not appear to have resulted from
intrauterine drug exposure that has been limited to the first trimester. These
patients should be asked to report pregnancies to their physicians as soon as
possible.
Symptomatic Hypotension:A patient receiving
BENICAR HCT® should be cautioned
that lightheadedness can occur, especially during the first days of therapy, and
that it should be reported to the prescribing physician. The patients should be
told that if syncope occurs, BENICAR HCT® should be discontinued until the physician has been
consulted.
All patients should be cautioned that inadequate fluid intake, excessive
perspiration, diarrhea or vomiting can lead to an excessive fall in blood
pressure, with the same consequences of light-headedness and possible
syncope.
Drug Interactions
Olmesartan medoxomilNo significant drug interactions were reported in studies in
which olmesartan medoxomil was co-administered with hydrochlorothiazide, digoxin
or warfarin in healthy volunteers. The bioavailability of olmesartan was not
significantly altered by the co-administration of antacids [Al(OH)3/Mg(OH)2]. Olmesartan medoxomil is not
metabolized by the cytochrome P450 system and has no effects on P450 enzymes;
thus, interactions with drugs that inhibit, induce or are metabolized by those
enzymes are not expected.
HydrochlorothiazideWhen administered concurrently the following drugs may interact
with thiazide diuretics:
Alcohol, Barbiturates, Or Narcotics–
potentiation of orthostatic hypotension may occur.
Antidiabetic Drugs (oral agents and insulin)–
dosage adjustment of the antidiabetic drug may be required.
Other Antihypertensive Drugs– additive effect
or potentiation.
Cholestyramine and Colestipol Resins–
absorption of hydrochlorothiazide is impaired in the presence of anionic
exchange resins. Single doses of either cholestyramine or colestipol resins bind
the hydrochlorothiazide and reduce its absorption from the gastrointestinal
tract by up to 85 and 43 percent, respectively.
Corticosteroids, ACTH– intensified electrolyte
depletion, particularly hypokalemia.
Pressor Amines (e.g. Norepinephrine)– possible
decreased response to pressor amines but not sufficient to preclude their
use.
Skeletal Muscle Relaxants, Non depolarizing (e.g.
Tubocurarine)– possible increased responsiveness to the muscle
relaxant.
Lithium– should not generally be given with
diuretics. Diuretic agents reduce the renal clearance of lithium and add a high
risk of lithium toxicity. Refer to the package insert for lithium preparations
before use of such preparation with olmesartan
medoxomil-hydrochlorothiazide.
Non-steroidal Anti-inflammatory Drugs– in some
patients the administration of a non-steroidal anti-inflammatory agent can
reduce the diuretic, natriuretic and antihypertensive effects of loop,
potassium-sparing and thiazide diuretics. Therefore, when olmesartan
medoxomil-hydrochlorothiazide tablets and non-steroidal anti-inflammatory agents
are used concomitantly, the patients should be observed closely to determine if
the desired effect of the diuretic is obtained.
Carcinogenesis, Mutagenesis, Impairment of
Fertility
Olmesartan
medoxomil-hydrochlorothiazideNo carcinogenicity studies with olmesartan
medoxomil-hydrochlorothiazide have been conducted.
Olmesartan medoxomil-hydrochlorothiazide in a ratio of 20:12.5 was negative
in the Salmonella-Escherichia coli/mammalian
microsome reverse mutation test up to the maximum recommended plate
concentration for the standard assays. Olmesartan medoxomil and
hydrochlorothiazide were tested individually and in combination ratios of
40:12.5, 20:12.5 and 10:12.5, for clastogenic activity in the in vitro Chinese hamster lung (CHL) chromosomal aberration
assay. A positive response was seen for each component and combination ratio.
However, no synergism in clastogenic activity was detected between olmesartan
medoxomil and hydrochlorothiazide at any combination ratio.
Olmesartan medoxomil-hydrochlorothiazide in a ratio of 20:12.5, administered
orally, tested negative in the in vivo mouse bone
marrow erythrocyte micronucleus assay at administered doses of up to 3144
mg/kg.
No studies of impairment of fertility with olmesartan
medoxomil-hydrochlorothiazide have been conducted.
Olmesartan medoxomilOlmesartan medoxomil was not carcinogenic when administered by
dietary administration to rats for up to 2 years. The highest dose tested (2000
mg/kg/day) was, on a mg/m2 basis, about 480 times the
maximum recommended human dose (MRHD) of 40 mg/day. Two carcinogenicity studies
conducted in mice, a 6-month gavage study in the p53 knockout mouse and a
6-month dietary administration study in the Hras2 transgenic mouse, at doses of
up to 1000 mg/kg/day (about 120 times the MRHD), revealed no evidence of a
carcinogenic effect of olmesartan medoxomil.
Both olmesartan medoxomil and olmesartan tested negative in the in vitro Syrian hamster embryo cell transformation assay
and showed no evidence of genetic toxicity in the Ames (bacterial mutagenicity)
test. However, both were shown to induce chromosomal aberrations in cultured
cells in vitro (Chinese hamster lung) and both tested
positive for thymidine kinase mutations in the in
vitro mouse lymphoma assay. Olmesartan medoxomil tested negative in vivo for mutations in the MutaMouse intestine and
kidney, and for clastogenicity in mouse bone marrow (micronucleus test) at oral
doses of up to 2000 mg/kg (olmesartan not tested).
Fertility of rats was unaffected by administration of olmesartan medoxomil at
dose levels as high as 1000 mg/kg/day (240 times the MRHD) in a study in which
dosing was begun 2 (female) or 9 (male) weeks prior to mating.
HydrochlorothiazideTwo-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.
Hydrochlorothiazide was not genotoxic in vitro in
the Ames mutagenicity assay of Salmonella typhimurium
strains TA 98, TA 100, TA 1535, TA 1537 and TA 1538, or in the Chinese Hamster
Ovary (CHO) test for chromosomal aberrations. It was also not genotoxic in vivo in assays using mouse germinal cell chromosomes,
Chinese hamster bone marrow chromosomes, or the Drosophila sex-linked recessive lethal trait gene. Positive
test results were obtained in the in vitro CHO Sister
Chromatid Exchange (clastogenicity) assay, the Mouse Lymphoma Cell
(mutagenicity) assay and the Aspergillus nidulans
non-disjunction assay.
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 mating 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 olmesartan is excreted in human milk, but
olmesartan is secreted at low concentration in the milk of lactating rats.
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.
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
Clinical studies of BENICAR HCT® did not include sufficient numbers of subjects aged 65
and over to determine whether they respond differently from younger subjects.
Other reported clinical experience has not identified differences in responses
between the elderly and younger patients. In general, dose selection for an
elderly patient should be cautious, usually starting at the low end of the
dosing range, reflecting the greater frequency of decreased hepatic, renal or
cardiac function and of concomitant diseases or other drug therapy.
Olmesartan and hydrochlorothiazide are substantially excreted by the kidney,
and the risk of toxic reactions to this drug may be greater in patients with
impaired renal function.