metolazone

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metolazone

Metenix (UK), Zaroxolyn

Pharmacologic class: Thiazide-like diuretic

Therapeutic class: Diuretic, antihypertensive

Pregnancy risk category B

Action

Inhibits electrolyte reabsorption from ascending loop of Henle and decreases reabsorption of sodium and potassium in distal renal tubules, increasing plasma osmotic pressure and promoting diuresis

Availability

Tablets: 2.5 mg, 5 mg, 10 mg

Indications and dosages

Hypertension

Adult: 2.5 to 5 mg P.O. daily.

Edema caused by heart failure or renal disease

Adults: 5 to 20 mg P.O. daily

Contraindications

• Hypersensitivity to drug

• Hepatic coma or precoma

• Anuria

Precautions

Use cautiously in:

• severe hepatic or renal impairment, gout, hyperparathyroidism, glucose tolerance abnormalities, fluid or electrolyte imbalances, bipolar disorders

• elderly patients

• pregnant or breastfeeding patients

• children (safety not established).

Administration

• Give in morning to avoid frequent nighttime urination.

• Discontinue drug before parathyroid function tests are performed.

• Be aware that metolazone is the only thiazide-like diuretic that may cause diuresis in patients with glomerular filtration rates below 20 ml/minute.

Adverse reactions

CNS: drowsiness, lethargy, vertigo, paresthesia, weakness, headache, fatigue

CV: chest pain, hypotension, palpitations, venous thrombosis, arrhythmias

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

GU: polyuria, nocturia, erectile dysfunction, decreased libido

Hematologic: aplastic anemia, leukopenia, agranulocytosis

Hepatic: hepatitis

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

Musculoskeletal: muscle cramps

Skin: photosensitivity, rashes

Other: chills

Interactions

Drug-drug. Amphotericin B, corticosteroids, mezlocillin, piperacillin, ticarcillin: additive hypokalemia

Antigout drugs: increased uric acid level

Antihypertensives, nitrates: additive hypotension

Digoxin: increased risk of digoxin toxicity

Lithium: decreased lithium excretion, increased risk of lithium toxicity

Drug-diagnostic tests. Bilirubin, calcium, cholesterol, creatinine, low-density lipoproteins, triglycerides, uric acid: increased levels

Blood glucose, urine glucose: increased levels in diabetic patients

Magnesium, potassium, protein-bound iodine, sodium, urinary calcium: decreased levels

Drug-food. Any food: increased metolazone absorption

Drug-herbs. Aloe, cascara sagrada, senna: increased risk of hypokalemia

Drug-behaviors. Sun exposure: increased risk of photosensitivity

Patient monitoring

• Monitor baseline and periodic electrolyte, blood urea nitrogen, glucose, and uric acid levels.

• Evaluate blood pressure regularly.

Watch for signs and symptoms of hypokalemia, which may necessitate potassium supplements, potassium-rich diet, or potassium-sparing diuretic. Hypokalemia is particularly dangerous to patients who are on digitalis or have had ventricular arrhythmias.

• Assess patient for fluid and electrolyte imbalances.

Patient teaching

• Advise patient to take in morning to avoid frequent nighttime urination.

• Tell patient he may take with food or milk to prevent GI upset.

Instruct patient to report muscle pain, weakness, or cramps; nausea; vomiting; diarrhea; dizziness; restlessness; excessive thirst; fatigue; drowsiness; increased pulse; or irregular heart beats.

• Inform patient that drug may cause gout attacks. Advise him to report sudden joint pain.

• Instruct patient to use sunscreen and protective clothing to avoid photosensitivity.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.

metolazone

/me·to·la·zone/ (mĕ-to´lah-zōn) a sulfonamide derivative with actions similar to the thiazide diuretics; used in the treatment of hypertension and edema.

metolazone

[mətō′ləzōn]
a diuretic.
indications It is prescribed for the treatment of edema and mild to moderate high blood pressure.
contraindications Anuria or known hypersensitivity to this drug, to thiazides, or to sulfonamides prohibits its use.
adverse effects Among the more serious adverse effects are hypokalemia, hyperglycemia, hyperuricemia, and allergic reactions.

metolazone

A diuretic drug similar to the thiazide group used to treat high blood pressure (HYPERTENSION). A brand name is Metenix.

metolazone

a diuretic and saluretic.