Oretic

Oretic,

trademark for a diuretic (hydrochlorothiazide).

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hydrochlorothiazide

Apo-Hydro (CA), Diuchlor H (CA), Hydro-Par, Microzide, Neo-Codema (CA), Novo-Hydrazide (CA), Oretic, Urozide (CA)

Pharmacologic class: Thiazide diuretic

Therapeutic class: Diuretic, antihypertensive

Pregnancy risk category B

Action

Increases sodium and water excretion by inhibiting sodium reabsorption in distal tubules; promotes excretion of chloride, potassium, magnesium, and bicarbonate. Also may produce arteriolar dilation, reducing blood pressure.

Availability

Capsules: 12.5 mg

Oral solution: 10 mg/ml, 100 mg/ml

Tablets: 25 mg, 50 mg, 100 mg

⊘Indications and dosages

➣ Edema caused by heart failure, renal dysfunction, cirrhosis, corticosteroid therapy, or estrogen therapy

Adults: 25 to 100 mg P.O. daily as a single dose or in divided doses. Maximum dosage is 200 mg/day.

➣ Mild to moderate hypertension

Adults: Initially, 12.5 mg daily P.O.; then, based on blood pressure response, may give 12.5 to 50 mg/day P.O. Higher dosages may be given in refractory cases.

Children ages 6 months to 12 years: 2.2 mg/kg P.O. daily in two divided doses

Children younger than 6 months: Up to 3.3 mg/kg P.O. daily in two divided doses

Off-label uses

• Hypercalcemia
• Ménière's disease

Contraindications

• Hypersensitivity to drug, other thiazides, sulfonamides, or tartrazine
• Renal decompensation or anuria

Precautions

Use cautiously in:
• renal or severe hepatic impairment, fluid or electrolyte imbalances, gout, systemic lupus erythematosus, hyperparathyroidism, glucose tolerance abnormalities, bipolar disorder
• pregnant or breastfeeding patients.

Administration

• Give with food or milk if GI upset occurs.
• Administer early in day so diuretic effect doesn't disturb sleep.

Route	Onset	Peak	Duration
P.O.	2 hr	3-6 hr	6-12 hr

Adverse reactions

CNS: dizziness, drowsiness, lethargy, headache, insomnia, nervousness, vertigo, asthenia, asterixis, paresthesias, confusion, fatigue, encephalopathy

CV: chest pain, orthostatic hypotension, ECG changes, thrombophlebitis, arrhythmias

EENT: nystagmus

GI: nausea, vomiting, epigastric distress, anorexia, pancreatitis

GU: polyuria, nocturia, erectile dysfunction, loss of libido, renal failure

Hematologic: anemia, hemolytic anemia, agranulocytosis, leukopenia, thrombocytopenia

Hepatic: jaundice, hepatitis

Metabolic: dehydration, gout, hyperglycemia, hypokalemia, hypocalcemia, hypovolemia, hypomagnesemia, hyponatremia, hypophosphatemia, hyperuricemia, hypochloremic alkalosis

Musculoskeletal: muscle cramps

Skin: photosensitivity, urticaria, rash, dermatitis, purpura, alopecia, flushing

Other: fever, weight loss, anaphylaxis

Interactions

Drug-drug. Allopurinol: increased risk of hypersensitivity reaction

Amphotericin B, corticosteroids, digoxin, mezlocillin, piperacillin, ticarcillin: increased risk of hypokalemia

Antihypertensives, barbiturates, nitrates, opioids: increased hypotension

Cholestyramine, colestipol: decreased hydrochlorothiazide absorption

Digoxin: increased risk of hypokalemia

Lithium: decreased excretion and increased blood level of lithium

Nonsteroidal anti-inflammatory drugs: decreased hydrochlorothiazide efficacy

Drug-diagnostic tests. Bilirubin, blood and urine glucose (in diabetic patients), calcium, creatinine, uric acid: increased levels

Cholesterol, low-density lipoproteins, magnesium, potassium, protein-bound iodine, sodium, triglycerides, urinary calcium: decreased levels

Drug-herbs. Dandelion: interference with diuretic activity

Ginkgo: decreased antihypertensive effect

Licorice, stimulant laxative herbs (aloe, cascara sagrada, senna): increased risk of hypokalemia

Drug-behaviors. Alcohol use: increased hypotension

Sun exposure: increased risk of photosensitivity

Patient monitoring

• Monitor blood pressure, fluid intake and output, and daily weight.
• Assess electrolyte levels, especially potassium. Monitor for signs and symptoms of hypokalemia.
• Monitor blood urea nitrogen and creatinine levels.
• Check blood glucose level in diabetic patients.
• Assess for signs and symptoms of gout attacks in patients with gouty arthritis.

Patient teaching

• Advise patient to take with food or milk if GI upset occurs.
• Tell patient to take early in day to avoid nighttime urination.
• Instruct patient to track intermittent doses on calendar.
• Tell patient to weigh himself daily, at same time on same scale and wearing same clothes.
☞ Instruct patient to report decreased urination, swelling, unusual bleeding or bruising, dizziness, fatigue, numbness, and muscle weakness or cramping.
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure decrease.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.