Used for emergency lowering of DBP in hypertensive crises (hypertensive emergencies) in adults with severe, nonmalignant or malignant (severe accelerated) hypertension and in children with acute severe hypertension. Situations in which immediate reduction in BP is needed to prevent or limit target organ damage include hypertensive encephalopathy, intracranial hemorrhage, stroke, unstable angina pectoris, AMI, acute left ventricular failure with pulmonary edema, dissecting aortic aneurysm, head trauma, and life-threatening arterial bleeding.
Intended for short-term use in hospitalized patients only.
Other IV hypotensive agents generally are preferred unless intensive monitoring is not available.
Has been used successfully for the management of hypertensive emergencies associated with pregnancy (e.g., preeclampsia, eclampsia) when delivery is imminent, but safe use in pregnant women not clearly established and other antihypertensives (e.g., IV hydralazine) are preferred. (See Pregnancy under Cautions.)
May be of particular value in patients with malignant hypertension associated with renal impairment. Usually effective in patients who are resistant to other hypotensive agents.
Has been used IV in the management of hypertensive urgencies†, which are situations (e.g., upper levels of severe hypertension, hypertension with optic disk edema, progressive target organ complications, severe perioperative hypertension) in which it is desirable to reduce BP within a few hours. However, such urgencies usually can be managed with oral doses of drugs with a relatively rapid onset of action.
Has also been used orally† for the management of hypertension; however, its hyperglycemic and sodium-retaining effects make it unsuitable for chronic therapy.
Adults: Used orally in the management of hypoglycemia caused by hyperinsulinism associated with inoperable islet cell adenoma or carcinoma, or extrapancreatic malignancy.
Infants and children: Used orally in the management of hypoglycemia associated with leucine sensitivity, islet cell hyperplasia, nesidioblastosis, extrapancreatic malignancy, islet cell adenoma, or adenomatosis.
Adults and children: May be used preoperatively as a temporary measure, and postoperatively if hypoglycemia persists.
Should be used only after diagnosis of hypoglycemia caused by one of the above conditions has been definitely established and when specific medical or surgical management has been unsuccessful or is not feasible.
Dosage and Administration
General
Since repeated administration of diazoxide may cause sodium and water retention, administer a diuretic to patients receiving multiple doses of the drug IV or orally.
Severe Hypertension
Adjust dosage according to the degree of hypertension and the patient’s BP response and tolerance.
Patient should remain supine during, immediately following, and preferably for ≥1 hour after IV administration of the drug. When furosemide is administered in conjunction with IV diazoxide, patient should remain supine for 8–10 hours.
Monitor BP closely until it has stabilized and hourly thereafter. In ambulatory patients, perform final BP measurement while the patient is standing.
Investigate additional decreases in BP 30 minutes or more after injection for causes other than the effects of the drug.
Use principally in hospitals or where there are adequate facilities readily available for the management of hypotension induced by the drug. Attempt to achieve desired BP reduction over as long a period of time as is compatible with the patient’s clinical status (manufacturer suggests at least several hours and preferably 1 or 2 days).
Replace IV diazoxide treatment with oral hypotensive agents as soon as adequate control of BP is achieved; administration of diazoxide for >4–5 days seldom necessary.
Hypoglycemia
Individualize oral dosage based on severity of condition, blood glucose concentration, and clinical response of patient.
Observe patients closely when treatment is initiated. Monitor blood glucose concentrations until patient's condition has stabilized; usually requires several days.
If hyperglycemia or glycosuria occurs, reduction in dosage may be required to avoid progession to ketoacidosis or hyperosmolar coma.
Discontinue drug if not effective after 2–3 weeks. In patients who respond to diazoxide, therapy must be continued for several years. The drug may be discontinued when insulin-glucose ratios and insulin responses to provocative tests are normal.
Adjust dosage as necessary if patients are changed from one oral dosage formulation to another (capsules, suspension).
Administration
Administer orally or by IV injection. Do not administer IM, sub-Q, or into body cavities.
IV Administration
Administer undiluted by rapid IV injection over a period of ≤30 seconds into a peripheral vein via an established IV line.
Avoid extravasation into subcutaneous tissues.
Dosage
Pediatric Patients
Severe Hypertension
IV
“Minibolus” regimen: 1–3 mg/kg (up to 150 mg per dose) or 50–100 mg total every 5–15 minutes until adequate reduction in BP (e.g., DBP <100 mm Hg) is achieved; the use of 300-mg doses is no longer recommended. Subsequent dosing intervals depend on individual patient response. Repeated administration at 4- to 24-hour intervals generally maintains BP below pretreatment levels.
Hypertensive emergencies: Initial goal is to reduce mean arterial BP by no more than 25% within minutes to 1 hour, followed by further reduction if stable toward 160/100 mm Hg within the next 2–6 hours. Avoid excessive reductions in BP. If this BP is well tolerated and the patient is clinically stable, may administer additional doses to achieve further gradual BP reductions toward normal in the next 24–48 hours.
Aortic dissection: Goal is to reduce systolic pressure to <100 mm Hg if tolerated.
Hypoglycemia
Oral
Children: Usual initial dosage is 3 mg/kg daily given in 3 equal doses every 8 hours.
Children: Usual maintenance dosage is 3–8 mg/kg daily given in 2 or 3 divided doses every 12 or 8 hours, respectively.
Refractory hypoglycemia in children: May require high doses; dosages as high as 10–15 mg/kg daily have been used.
Infants and neonates: Usual initial dosage is 10 mg/kg daily given in 3 equal doses every 8 hours.
Infants and neonates: Usual maintenance dosage is 8–15 mg/kg daily given in 2 or 3 equal doses every 12 or 8 hours, respectively.
Adults
Severe Hypertension
IV
“Minibolus” regimen: 1–3 mg/kg (up to 150 mg per dose) or 50–100 mg total every 5–15 minutes until adequate reduction in BP (e.g., DBP <100 mm Hg) is achieved; the use of 300-mg doses is no longer recommended. Subsequent dosing intervals depend on individual patient response. Repeated administration at 4- to 24-hour intervals generally maintains BP below pretreatment levels.
Hypertensive emergencies: Initial goal is to reduce mean arterial BP by no more than 25% within minutes to 1 hour, followed by further reduction if stable toward 160/100 mm Hg within the next 2–6 hours. Avoid excessive reductions in BP. If this BP is well tolerated and the patient is clinically stable, may administer additional doses to achieve further gradual BP reductions toward normal in the next 24–48 hours.
Aortic dissection: Goal is to reduce systolic pressure to <100 mm Hg if tolerated.
Severe hypertension: Has been administered by constant IV infusion† at rates ranging from 7.5–30 mg/minute in various dosing schedules. Consult specialized references for specific recommendations.
Replace IV diazoxide with oral hypotensive agent therapy as soon as adequate control of BP is achieved; administration for >4–5 days seldom necessary.
Hypoglycemia
Oral
Usual initial dosage: 3 mg/kg daily given in 3 equal doses every 8 hours (i.e., approximately 200 mg daily for an average adult).
Usual maintenance dosage: 3–8 mg/kg daily given in 2 or 3 equal doses every 12 or 8 hours, respectively.
Refractory hypoglycemia: May require high doses; dosages as high as 10–15 mg/kg daily have been used.
Prescribing Limits
Pediatric Patients
Severe Hypertension
IV
150 mg every 5–15 minutes until adequate reduction in BP is achieved.
Maximum duration of therapy: 10 days.
Adults
Severe Hypertension
IV
150 mg every 5–15 minutes until adequate reduction in BP is achieved.
Maximum duration of therapy: 10 days.
Special Populations
Renal Impairment
Patients with Hypoglycemia
Oral
Since plasma half-life is prolonged with renal impairment, consider reduced dosage.
Cautions
Contraindications
IV and oral: Hypersensitivity to the drug, other thiazide derivatives, or other sulfonamide-derived agents.
Use caution when reducing severely elevated BP; maximum recommended single dose of diazoxide is 150 mg. (See Dosage under Dosage and Administration.) Angina and myocardial and cerebral infarction have occurred in patients receiving single IV doses of 300 mg. Myocardial ischemia may be manifested by angina, atrial and/or ventricular arrhythmias, and marked ECG changes. Use caution when administering diazoxide IV to patients with recent MI, as the drug may cause an increase in myocardial injury.
Use IV drug with caution in patients with impaired cerebral or cardiac circulation. Such patients include those in whom abrupt reductions in BP may be hazardous or in whom mild tachycardia or decreased blood perfusion may be deleterious. If excessive reduction in BP requiring therapy occurs, place the patient in Trendelenburg position; administer sympathomimetic agents (e.g., dopamine, norepinephrine) if necessary.
Sodium and water retention occurs frequently in patients (adults and young infants), and may result in edema, weight gain, and CHF (especially in uremic patients). (See Renal Impairment under Cautions.)
Hyperglycemia
Occurs frequently in patients receiving IV diazoxide for management of hypertension.
Monitor blood glucose concentrations after IV or oral therapy. In patients receiving oral therapy for the treatment of hypoglycemia, monitor blood glucose concentrations carefully until the patient’s condition has stabilized.
Usually mild and subsides without treatment. May require administration of oral hypoglycemic agents or insulin, especially in diabetic patients or those receiving repeated doses of diazoxide.
Ketoacidosis and nonketotic hyperosmolar coma reported with recommended oral dosage, usually during intercurrent illness.
If ketoacidosis occurs, administer insulin and restore fluid and electrolyte balance immediately.
Sensitivity Reactions
Rash, leukopenia, fever.
General Precautions
Metabolic and Electrolyte Effects
Repeated administration may cause sodium and fluid retention. (See Cardiovascular Effects under Cautions.)
Administer a diuretic to patients receiving multiple doses of diazoxide IV or orally. Consider the possibility of potentiation of hypotensive, hyperglycemic, and hyperuricemic effects in patients receiving concomitant diuretic therapy.
Administer with caution to patients in whom retention of sodium and water may be hazardous (e.g., those with impaired cardiac reserve).
Exercise caution when administering to uremic patients, since these patients may experience a greater hypotensive effect. Hematologic monitoring may be advisable in patients who receive the drug for longer than a few days; monitor serum uric acid concentration in patients with hyperuricemia or a history of gout.
Local Effects
Avoid extravascular injection or leakage. If extravasation occurs, apply warm compresses; local administration of sodium chloride injection or a local anesthetic to dilute the extravasated alkaline solution has been used to relieve the pain.
May cause cessation of uterine contractions during labor; administration of oxytocic agents may be required.
Manufacturer states that IV diazoxide is not indicated for use in pregnancy. Caution advised if oral diazoxide administered during labor and delivery.
Lactation
Not known whether diazoxide is distributed into milk. Discontinue nursing or the drug.
Renal Impairment
Nondiabetic hypertensive patients with impaired renal function may develop diabetic ketoacidosis following multiple IV or oral doses of diazoxide. Observe patients carefully for possible development of severe hyperglycemia.
Avoid prolonged hypotension since it may aggravate preexisting renal failure.
Monitor serum electrolyte concentrations in patients with renal impairment. Such patients may require potent diuretics such as furosemide or ethacrynic acid rather than thiazide diuretics to manage sodium and fluid retention.
Common Adverse Effects
IV: Hypotension, nausea and vomiting, dizziness, weakness reported with previously recommended regimen employing 300-mg dose; use of 300-mg IV doses no longer recommended. Hyperglycemia (usually mild, subsides without treatment).
Oral: Sodium and fluid retention.
Interactions
Specific Drugs and Laboratory Tests
Drug or Test
Interaction
Comments
β-Adrenergic blocking agents
May potentiate hypotensive effect
Do not administer within 6 hours of β-adrenergic blockers
Diazoxide is less bound to cord plasma proteins than to adult plasma proteins.
In patients with chronic uremia, there is a substantial reduction of plasma protein binding, probably resulting from decreased serum albumin in these patients.
Elimination
Metabolism
Partially metabolized by oxidation and sulfate conjugation and excreted slowly in urine by glomerular filtration as unchanged drug and metabolites.
Elimination Route
In one patient, 2% of an orally administered dose of diazoxide was recovered in feces.
Half-life
21–48 hours in adults with normal renal function. The high degree of protein binding is responsible for the prolonged half-life.
Special Populations
In pediatric patients, terminal elimination half-life may be somewhat shorter than in adults.
In patients with renal impairment, half-life is prolonged in proportion to decreases in Clcr. Diazoxide and its metabolites are removed by hemodialysis and peritoneal dialysis, but dialysance is relatively low because of extensive protein binding.
Stability
Storage
Oral
Capsules and Suspension
25°C (may be exposed to 15–30°C); protect from light. Should not use darkened oral suspensions since they may be subpotent.
Parenteral
Solution for Injection
25°C (may be exposed to 15–30°C); protect from light and freezing. Should not use darkened injections since they may be subpotent.
Compatibility
For information on systemic interactions resulting from concomitant use, see Interactions.
Reduces peripheral vascular resistance and BP as a result of a direct vasodilatory effect on smooth muscle in peripheral arterioles.
Inhibits contractions in both the term uterus during labor and the nongravid uterus.
Increases heart rate, cardiac output, and left ventricular ejection rate, probably as a result of a reflex response to decreased peripheral vascular resistance. In high doses in animals, has caused myocardial necrosis due to ischemia.
Causes sodium and water retention and decreased urinary output, which can result in expansion of plasma and extracellular fluid volume, edema, and CHF. Reduces excretion of potassium, chloride, bicarbonate, para-aminohippuric acid, and uric acid.
Increases blood glucose concentration by inhibiting pancreatic insulin secretion, stimulating release of catecholamines, and/or increasing hepatic release of glucose. Markedly inhibits glucose- and glucagon-induced insulin secretion.
Decreases cortisol secretion.
Increases plasma free fatty acid concentrations.
Advice to Patients
Importance of taking oral diazoxide regularly and of not skipping doses or taking extra doses.
Importance of not sharing the drug with others.
Importance of following dietary instructions.
Importance of compliance with dietary instructions.
In patients receiving IV diazoxide, importance of remaining supine during, immediately following, and preferably for at least 1 hour after administration of the drug.
In patients treated for hypoglycemia, importance of testing blood and urine for glucose and ketones regularly and of reporting results to their clinicians.
In patients being treated for hypoglycemia, importance of reporting any signs or symptoms of adverse effects (i.e., increased urinary frequency, increased thirst, fruity breath odor).
Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.
Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs and herbal supplements, as well as any concomitant illnesses.
Importance of informing patients of other important precautionary information. (See Cautions.)
Preparations
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
† Use is not currently included in the labeling approved by the US Food and Drug Administration.
Remember, keep this and all other medicines out of the reach of children,
never share your medicines with others, and use this medication only for the indication prescribed.
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