United States - English - NLM (National Library of Medicine)
HYDROCHLOROTHIAZIDE- hydrochlorothiazide capsule
Hydrochlorothiazide, USP is the 3,4-dihydro derivative of chlorothiazide. Its chemical name is 6-
Chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Its molecular formula is
C7H8ClN3O4S2; its molecular weight is 297.74; and its structural formula is:
[Structure of Hydrochlorothiazide]
It is a white, or practically white, crystalline powder which is slightly soluble in water, but freely
soluble in sodium hydroxide solution.
Hydrochlorothiazide is supplied as 12.5 mg capsules for oral use.
Inactive ingredients: microcrystalline cellulose, pregelatinized starch, colloidal silicon dioxide,
magnesium stearate, gelatin, titanium dioxide, sodium lauryl sulfate and black iron oxide.
Hydrochlorothiazide blocks the reabsorption of sodium and chloride ions, and it thereby increases the
quantity of sodium traversing the distal tubule and the volume of water excreted. A portion of the
additional sodium presented to the distal tubule is exchanged there for potassium and hydrogen ions.
With continued use of hydrochlorothiazide and depletion of sodium, compensatory mechanisms tend to
increase this exchange and may produce excessive loss of potassium, hydrogen and chloride ions.
Hydrochlorothiazide also decreases the excretion of calcium and uric acid, may increase the excretion
of iodide and may reduce glomerular filtration rate. Metabolic toxicities associated with excessive
electrolyte changes caused by hydrochlorothiazide have been shown to be dose-related.
Pharmacokinetics and Metabolism
Hydrochlorothiazide is well absorbed (65% to 75%) following oral administration. Absorption of
hydrochlorothiazide is reduced in patients with congestive heart failure.
Peak plasma concentrations are observed within 1 to 5 hours of dosing, and range from 70 to 490 ng/mL
following oral doses of 12.5 to 100 mg. Plasma concentrations are linearly related to the administered
dose. Concentrations of hydrochlorothiazide are 1.6 to 1.8 times higher in whole blood than in plasma.
Binding to serum proteins has been reported to be approximately 40% to 68%. The plasma elimination
half-life has been reported to be 6 to 15 hours. Hydrochlorothiazide is eliminated primarily by renal
pathways. Following oral doses of 12.5 to 100 mg, 55% to 77% of the administered dose appears in
urine and greater than 95% of the absorbed dose is excreted in urine as unchanged drug. In patients with
renal disease, plasma concentrations of hydrochlorothiazide are increased and the elimination half-life
When hydrochlorothiazide is administered with food, its bioavailability is reduced by 10%, the
maximum plasma concentration is reduced by 20%, and the time to maximum concentration increases
from 1.6 to 2.9 hours.
Acute antihypertensive effects of thiazides are thought to result from a reduction in blood volume and
cardiac output, secondary to a natriuretic effect, although a direct vasodilatory mechanism has also been
proposed. With chronic administration, plasma volume returns toward normal, but peripheral vascular
resistance is decreased. The exact mechanism of the antihypertensive effect of hydrochlorothiazide is
Thiazides do not affect normal blood pressure. Onset of action occurs within 2 hours of dosing, peak
effect is observed at about 4 hours, and activity persists for up to 24 hours.
In an 87 patient 4-week double-blind, placebo controlled, parallel group trial, patients who received
hydrochlorothiazide had reductions in seated systolic and diastolic blood pressure that were
significantly greater than those seen in patients who received placebo. In published placebo-controlled
trials comparing 12.5 mg of hydrochlorothiazide to 25 mg, the 12.5 mg dose preserved most of the
placebo-corrected blood pressure reduction seen with 25 mg.
Hydrochlorothiazide capsules are indicated in the management of hypertension either as the sole
therapeutic agent, or in combination with other antihypertensives. Unlike potassium sparing combination
diuretic products, hydrochlorothiazide capsules may be used in those patients in whom the development
of hyperkalemia cannot be risked, including patients taking ACE inhibitors.
Usage in Pregnancy: The routine use of diuretics in an otherwise healthy woman is inappropriate and
exposes mother and fetus to unnecessary hazard. Diuretics do not prevent development of toxemia of
pregnancy, and there is no satisfactory evidence that they are useful in the treatment of developed
Edema during pregnancy may arise from pathological causes or from the physiologic and mechanical
consequences of pregnancy. Diuretics are indicated in pregnancy when edema is due to pathologic
causes, just as they are in the absence of pregnancy. Dependent edema in pregnancy resulting from
restriction of venous return by the expanded uterus is properly treated through elevation of the lower
extremities and use of support hose; use of diuretics to lower intravascular volume in this case is
illogical and unnecessary. There is hypervolemia during normal pregnancy which is harmful to neither
the fetus nor the mother (in the absence of cardiovascular disease), but which is associated with edema,
including generalized edema in the majority of pregnant women. If this edema produces discomfort,
increased recumbency will often provide relief. In rare instances this edema may cause extreme
discomfort which is not relieved by rest. In these cases a short course of diuretics may provide relief
and may be appropriate.
Hydrochlorothiazide capsules are contraindicated in patients with anuria. Hypersensitivity to this
product or other sulfonamide derived drugs is also contraindicated.
Acute Myopia and Secondary Angle-Closure Glaucoma: Hydrochlorothiazide, a sulfonamide, can cause
an idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma.
Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within
hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision
loss. The primary treatment is to discontinue hydrochlorothiazide as rapidly as possible. Prompt
medical or surgical treatments may need to be considered if the intraocular pressure remains
uncontrolled. Risk factors for developing acute angle-closure glaucoma may include a history of
sulfonamide or penicillin allergy.
Diabetes and Hypoglycemia: Latent diabetes mellitus may become manifest and diabetic patients given
thiazides may require adjustment of their insulin dose.
Renal Disease: Cumulative effects of the thiazides may develop in patients with impaired renal function.
In such patients, thiazides may precipitate azotemia.
Electrolyte and Fluid Balance Status
In published studies, clinically significant hypokalemia has been consistently less common in patients
who received 12.5 mg of hydrochlorothiazide than in patients who received higher doses.
Nevertheless, periodic determination of serum electrolytes should be performed in patients who may be
at risk for the development of hypokalemia. Patients should be observed for signs of fluid or
electrolyte disturbances, i.e. hyponatremia, hypochloremic alkalosis, and hypokalemia and
Warning signs or symptoms of fluid and electrolyte imbalance include dryness of mouth, thirst,
weakness, lethargy, drowsiness, restlessness, 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, during
concomitant use of corticosteroid or adrenocorticotropic hormone (ACTH) or after prolonged therapy.
Interference with adequate oral electrolyte intake will also contribute to hypokalemia. Hypokalemia and
hypomagnesemia can provoke ventricular arrhythmias or sensitize or exaggerate the response of the
heart to the toxic effects of digitalis. Hypokalemia may be avoided or treated by potassium
supplementation or increased intake of potassium rich foods.
Dilutional hyponatremia is life-threatening and may occur in edematous patients in hot weather;
appropriate therapy is water restriction rather than salt administration, except in rare instances when the
hyponatremia is life-threatening. In actual salt depletion, appropriate replacement is the therapy of
Hyperuricemia or acute gout may be precipitated in certain patients receiving thiazide diuretics.
Impaired Hepatic Function
Thiazides should be used with caution in patients with impaired hepatic function. They can precipitate
hepatic coma in patients with severe liver disease.
Calcium excretion is decreased by thiazides, and pathologic changes in the parathyroid glands, with
hypercalcemia and hypophosphatemia, have been observed in a few patients on prolonged thiazide
When given 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 - Cholestyramine and colestipol resins bind the
hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent,
Corticosteroid, 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, nondepolarizing (e.g., tubocurarine) - possible increased responsiveness to
the muscle relaxant.
Lithium - generally should not be given with diuretics. Diuretic agents reduce the renal clearance of
lithium and greatly increase the risk of lithium toxicity. Refer to the package insert for lithium
preparations before use of such preparations with 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. When hydrochlorothiazide 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.
Drug/Laboratory Test Interactions - Thiazides should be discontinued before carrying out tests for
parathyroid function (see PRECAUTIONS, General).
Carcinogenesis, Mutagenesis, Impairment of Fertility
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
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
and in the Chinese Hamster Ovary (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. Positive test results were obtained only in the in vitro CHO Sister
Chromatid Exchange (clastogenicity) and in the Mouse Lymphoma Cell (mutagenicity) assays, using
concentrations of hydrochlorothiazide from 43 to 1300 mcg/mL, and in the Aspergillus nidulans non-
disjunction assay at an unspecified concentration.
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 Category B: Studies in which hydrochlorothiazide was orally administered to pregnant mice
and rats during their respective periods of major organogenesis at doses up to 3000 and 1000 mg
hydrochlorothiazide/kg, respectively, provided no evidence of harm to the fetus.
There are, however, no adequate and well-controlled studies in pregnant women. Because animal
reproduction studies are not always predictive of human response, this drug should be used during
pregnancy only if clearly needed.
Thiazides cross the placental barrier and appear in cord blood. There is a risk of fetal or neonatal
jaundice, thrombocytopenia, and possibly other adverse reactions that have occurred in adults.
Thiazides are excreted in breast milk. Because of the potential for serious adverse reactions in nursing
infants, a decision should be made whether to discontinue nursing or to discontinue
hydrochlorothiazide, taking into account the importance of the drug to the mother.
Safety and effectiveness in pediatric patients have not been established.
A greater blood pressure reduction and an increase in side effects may be observed in the elderly (i.e.,
>65 years) with hydrochlorothiazide. Starting treatment with the lowest available dose of
hydrochlorothiazide (12.5 mg) is therefore recommended. If further titration is required, 12.5 mg
increments should be utilized.
The adverse reactions associated with hydrochlorothiazide have been shown to be dose related. In
controlled clinical trials, the adverse events reported with doses of 12.5 mg hydrochlorothiazide once
daily were comparable to placebo. The following adverse reactions have been reported for doses of
hydrochlorothiazide 25 mg and greater and, within each category, are listed in the order of decreasing
Body as a whole: Weakness.
Cardiovascular: Hypotension including orthostatic hypotension (may be aggravated by alcohol,
barbiturates, narcotics or antihypertensive drugs).
Digestive: Pancreatitis, jaundice (intrahepatic cholestatic jaundice), diarrhea, vomiting, sialadenitis,
cramping, constipation, gastric irritation, nausea, anorexia.
Hematologic: Aplastic anemia, agranulocytosis, leukopenia, hemolytic anemia, thrombocytopenia.
Hypersensitivity: Anaphylactic reactions, necrotizing angiitis (vasculitis and cutaneous vasculitis),
respiratory distress including pneumonitis and pulmonary edema, photosensitivity, fever, urticaria, rash,
Metabolic: Electrolyte imbalance (see PRECAUTIONS), hyperglycemia, glycosuria, hyperuricemia.
Musculoskeletal: Muscle Spasm.
Nervous System/Psychiatric: Vertigo, paresthesia, dizziness, headache, restlessness.
Renal: Renal failure, renal dysfunction, interstitial nephritis (see WARNINGS).
Skin: Erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic
epidermal necrolysis, alopecia.
Special Senses: Transient blurred vision, xanthopsia.
Whenever adverse reactions are moderate or severe, thiazide dosage should be reduced or therapy
The most common signs and symptoms observed are those caused by electrolyte depletion
(hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. If
digitalis has also been administered, hypokalemia may accentuate cardiac arrhythmias.
In the event of overdosage, symptomatic and supportive measures should be employed. Emesis should
be induced or gastric lavage performed. Correct dehydration, electrolyte imbalance, hepatic coma and
hypotension by established procedures. If required, give oxygen or artificial respiration for respiratory
impairment. The degree to which hydrochlorothiazide is removed by hemodialysis has not been
The oral LD50 of hydrochlorothiazide is greater than 10 g/kg in the mouse and rat.
For Control of Hypertension: The adult initial dose of hydrochlorothiazide capsules is one capsule
given once daily whether given alone or in combination with other antihypertensives. Total daily doses
greater than 50 mg are not recommended.
Hydrochlorothiazide capsules USP, 12.5 mg are available as hard gelatin capsules with opaque white
cap and opaque white body imprinted with "U" on cap and "130" on the body in grey ink along the
Bottle of 100:
Bottle of 500:
Bottle of 1000:
Store at 200 to 250C (680 to 770F) [see USP Controlled Room Temperature]. Protect from light,
moisture, freezing, -200C (-40F). Keep container tightly closed.
Please address medical inquiries to Unichem's toll free # 1-866-562-4616.
UNICHEM LABORATORIES LTD.
Pilerne Ind. Estate, Pilerne,
Bardez, Goa 403 511, India
Hasbrouck Heights, NJ 07604
Product T ype
HUMAN PRESCRIPTION DRUG
Ite m Code (Source )
NDC:6 19 19 -58 0 (NDC:29 30 0 -130 )
Route of Administration
Active Ingredient/Active Moiety
Basis of Strength
Stre ng th
HYDRO CHLO RO THIAZIDE (UNII: 0 J48 LPH2TH) (HYDROCHLOROTHIAZIDE -
UNII:0 J48 LPH2TH)
HYDROCHLOROTHIAZIDE 12.5 mg
Stre ng th
FERRO SO FERRIC O XIDE (UNII: XM0 M8 7F357)
STARCH, CO RN (UNII: O8 232NY3SJ)
TITANIUM DIO XIDE (UNII: 15FIX9 V2JP)
CELLULO SE, MICRO CRYSTALLINE (UNII: OP1R32D6 1U)
MAGNESIUM STEARATE (UNII: 70 0 9 7M6 I30 )
SILICO N DIO XIDE (UNII: ETJ7Z6 XBU4)
SO DIUM LAURYL SULFATE (UNII: 36 8 GB5141J)
GELATIN (UNII: 2G8 6 QN327L)
no sco re
S hap e
S iz e
Marketing Start Date
Marketing End Date
NDC:6 19 19 -58 0 -9 0
9 0 in 1 BOTTLE; Type 0 : No t a Co mbinatio n Pro duct
0 8 /21/20 19
Marke ting Cate gory
Application Numbe r or Monograph Citation
Marke ting Start Date
Marke ting End Date
ANDA0 9 0 510
0 8 /21/20 19
Ad d re s s
Busine ss Ope rations
Dire c t_Rx
0 79 254320
re pa c k(6 19 19 -58 0 )