Medications and Drugs
GENERIC NAME: chlorthalidone
BRAND NAME: Hygroton
DRUG CLASS AND MECHANISM: Chlorthalidone is a diuretic
(water
pill). It works by reducing the kidneys' ability to hold on to water
and increasing the kidneys' production of urine (diuresis).
Chlorthalidone is closely related chemically to hydrochlorothiazide.
(Both are "thiazide" diuretics.) It was
approved by the FDA in 1960.
GENERIC AVAILABLE: yes
PRESCRIPTION: yes
PREPARATIONS: Tablets: 15mg, 25mg, 50mg, 100mg.
STORAGE: Tablets should be stored at room temperature,
15-30°C (59-86°F).
PRESCRIBED FOR: Chlorthalidone is used in the treatment of
high
blood pressure and congestive heart failure.
DOSING: The optimal dose of chlorthalidone varies greatly
from patient to patient.
DRUG INTERACTIONS: Chlorthalidone can cause lowering of
blood
potassium and magnesium levels because both potassium and magnesium
are lost in the urine. This is especially true in patients who are
taking at the same time another class of diuretics, called loop
diuretics such as furosemide (Lasix), bumetanide (Bumex), or
torsemide (Demadex) Low potassium and magnesium levels can lead to
abnormal heart rhythms, especially in patients taking digoxin
(Lanoxin).
Chlorthalidone reduces the kidney's
ability to eliminate lithium in the urine. As a result, patients
taking chlorthalidone at the same time as drugs containing lithium
may develop high levels of lithium and lithium toxicity.
Nonsteroidal antiinflammatory drugs (NSAIDs) such as ibuprofen
(Motrin),
naproxen (Naprosyn), and nabumetone (Relafen) can reduce the
effectiveness
of chlorthalidone though the reason for this is not clear.
PREGNANCY: Thiazide diuretics including chlorthalidone
cross the placenta and can cause jaundice in the fetus or newborn.
Therefore, chlorthalidone should not be used during pregnancy unless
absolutely necessary.
NURSING MOTHERS: The American Academy of Pediatrics
recommends
that breast-feeding be avoided during the first month of lactation
(nursing) in patients
receiving thiazide diuretics, including chlorthalidone, because
production of milk may be suppressed.
SIDE EFFECTS: Chlorthalidone generally is well tolerated.
Low blood levels of potassium, sodium, and
magnesium may occur during chlorthalidone
therapy due to their losses in urine. High blood calcium levels also
can occur, especially in
persons who are taking calcium supplements. Thiazide diuretics such
as chlorthalidone increase the levels of uric acid in the blood, but
gout (which is
caused by high levels of uric acid) rarely occurs. Chlorthalidone can
cause high blood sugars in diabetic patients. Other reported side
effects
include dizziness, lightheadedness, headache, fatigue, nausea,
vomiting, abdominal pain, and constipation.
Reference: FDA Prescribing Information
Last Editorial Review: 6/6/1999 7:41:00 PM
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Congestive Heart Failure - Read about congestive heart failure symptoms like fatigue, abdomen, leg and ankle swelling, shortness of breath, sleeplessness, increased urination, nausea, abdominal pain, and decreased appetite.
- hydrochlorothiazide, Hydrodiuril, Ezide, Hydro-Par, Microzide, and many combinations - Read about hydrochlorothiazide (Hydrodiuril, Ezide, Hydro-Par, Microzide), a drug used to treat excessive fluid accumulation and swelling (edema) of the body caused by heart failure, cirrhosis, chronic kidney failure, corticosteroid medications, and nephrotic syndrome.
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