diuretics (thiazide)

Contraindicated in:

Hypersensitivity (cross-sensitivity with other thiazides or sulfonamides may exist);
Some products contain tartrazine and should be avoided in patients with known intolerance;
Anuria;
Lactation: Lactation.

Use Cautiously in:

Renal impairment;
Hepatic impairment;
OB: Pregnancy (jaundice or thrombocytopenia may be seen in the newborn).

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypotension

Derm: photosensitivity, rash, SKIN CANCER (NONMELANOMA), STEVENS-JOHNSON SYNDROME (SJS)

EENT: acute angle-closure glaucoma (hydrochlorothiazide), acute myopia (hydrochlorothiazide)

Endo: hyperglycemia

F and E: hypokalemia, dehydration, hypercalcemia, hypochloremic alkalosis, hypomagnesemia, hyponatremia, hypophosphatemia, hypovolemia

GI: anorexia, cramping, hepatitis, nausea, pancreatitis, vomiting

Hemat: thrombocytopenia

Metab: hypercholesterolemia, hyperuricemia

MS: muscle cramps

Neuro: dizziness, drowsiness, lethargy, weakness

Interactions ⬆ ⬇

Drug-drug:

Additive hypotension with other antihypertensives, acute ingestion of alcohol, or nitrates.
Additive hypokalemia with corticosteroids, amphotericin B, or piperacillin/tazobactam.
May ↑ levels and risk of toxicity of lithium.
Cholestyramine or colestipol may ↓ absorption.
Hypokalemia ↑ risk of digoxin toxicity.
NSAIDs may ↓ effectiveness.

Availability ⬆ ⬇

Chlorothiazide

(Generic available)

Powder for injection: 500 mg/vial

Chlorthalidone

(Generic available)

Tablets: 12.5 mg; 15 mg; 25 mg; 50 mg
In combination with:
In combination with: atenolol (generic only); azilsartan (Edarbyclor). See Combination Drugs

Hydrochlorothiazide

(Generic available)

Tablets: 12.5 mg; 25 mg; 50 mg; 100 mg
Capsules: 12.5 mg
Oral suspension caramel-mint flavor: 10 mg/mL
In combination with:
numerous antihypertensive agents. See Combination Drugs.

Route/Dosage ⬆ ⬇

When used as a diuretic in adults, generally given daily, but may be given every other day or 2–3 days/wk.

Chlorothiazide

IV (Adults ): 500 mg–1 g/day in 1–2 divided doses.
IV (Children >6 mo): 4 mg/kg/day in 1–2 divided doses (maximum dose = 20 mg/kg/day) (unlabeled use).
IV (Neonates ≤6 mo): 1–4 mg/kg every 12 hr (maximum dose = 20 mg/kg/day) (unlabeled use).

Chlorthalidone

PO (Adults ): 12.5–100 mg once daily (daily doses above 25 mg are associated with greater likelihood of electrolyte abnormalities).

Hydrochlorothiazide

PO (Adults ): 12.5–100 mg/day in 1–2 divided doses (up to 200 mg/day); not to exceed 50 mg/day for hypertension; daily doses above 25 mg are associated with greater likelihood of electrolyte abnormalities.
PO (Children >6 mo): 1–3 mg/kg/day in 2 divided doses (not to exceed 37.5 mg/day).
PO (Children <6 mo): 1–3 mg/kg/day in 2 divided doses.

US Brand Names ⬆ ⬇

chlorothiazide: Diuril,

chlorthalidone (thiazide-like): Hemiclor, Thalitone,

hydroCHLOROthiazide: Inzirqo, ~~Microzide~~

Action ⬆ ⬇

Increases excretion of sodium and water by inhibiting sodium reabsorption in the distal tubule.
Promotes excretion of chloride, potassium, magnesium, and bicarbonate.
May produce arteriolar dilation.

Therapeutic effects:

Lowering of BP in hypertensive patients and diuresis with mobilization of edema.

Classifications ⬆ ⬇

Therapeutic Classification: antihypertensives, diuretics

Pharmacologic Classification: thiazide diuretics

Pharmacokinetics ⬆ ⬇

Absorption: All are rapidly absorbed after oral administration.

Distribution: Well distributed to tissues.

Metabolism/Excretion: All are excreted mainly unchanged by the kidneys.

Half-Life: Chlorothiazide: 1–2 hr; chlorthalidone: 35–50 hr; hydrochlorothiazide: 6–15 hr.

Time/Action Profile ⬆ ⬇

( diuretic effect)

ROUTE	ONSET	PEAK	DURATION
Chlorothiazide	15 min	30 min	2 hr
Chlorthalidone	2 hr	2 hr	48–72 hr
Hydrochlorothiazide‡	2 hr	3–6 hr	6–12 hr

‡Onset of antihypertensive effect is 3–4 days and does not become maximal for 7–14 days of dosing.

Patient/Family Teaching ⬆ ⬇

Explain purpose and side effects of medication to patient. Advise patient to read Patient Information before starting therapy. Advise patient to take medication at the same time each day. Take missed dose as soon as remembered but not just before next dose is due. Do not double doses.
Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care provider before taking other medications, especially cold preparations.
Advise patient to monitor weight biweekly and notify health care provider of significant changes.
- Caution patient to change positions slowly to minimize orthostatic hypotension. This may be potentiated by alcohol.
- Advise patient to use sunscreen and protective clothing to prevent photosensitivity reactions. Advise patient of importance of regular skin cancer screenings.
- Instruct patient to discuss dietary potassium requirements with health care provider (see Food Sources for Specific Nutrients).
- Instruct patient to notify health care provider of medication regimen before treatment or surgery.
- Advise patient to report rash, muscle weakness, cramps, nausea, vomiting, diarrhea, or dizziness to health care provider.
Hypertension: Advise patient to continue taking the medication even if feeling better. Medication controls but does not cure hypertension.
- Encourage patient to comply with additional interventions for hypertension (weight reduction, low-sodium diet, regular exercise, smoking cessation, moderation of alcohol consumption, stress management).
- Instruct patient and family/caregivers in correct technique for monitoring weekly BP.
Rep: Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected or if breastfeeding.

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Indications ⬇

Contraind./Precautions ⬆ ⬇

Adv. Reactions/Side Effects ⬆ ⬇

Interactions ⬆ ⬇

Availability ⬆ ⬇

Route/Dosage ⬆ ⬇

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Classifications ⬆ ⬇

Pharmacokinetics ⬆ ⬇

Time/Action Profile ⬆ ⬇

Patient/Family Teaching ⬆ ⬇

Pronunciation ⬆