Diazoxide

Diazoxide is a potassium channel opener that is primarily used in the medical management of hypoglycemia caused by insulinoma (a tumor that produces insulin) and in the treatment of hypertension (high blood pressure). It works by inhibiting insulin release from the pancreas, thereby increasing blood sugar levels, and by relaxing the smooth muscles of the blood vessels, leading to vasodilation and a reduction in blood pressure.

Medical Uses

Diazoxide is used in two main conditions:

• Hypoglycemia due to Insulinoma: It is used to prevent episodes of low blood sugar in patients with insulinoma, a rare tumor of the pancreas that secretes excess insulin.
• Hypertension: Although less commonly used today due to the availability of other antihypertensive drugs, diazoxide can be used in emergencies to lower blood pressure in patients with severe hypertension.

Mechanism of Action

Diazoxide works through several mechanisms:

• It opens ATP-sensitive potassium channels in the pancreatic beta cells. This action inhibits the release of insulin by stabilizing the membrane's electrical activity.
• In blood vessels, the opening of potassium channels leads to the relaxation of smooth muscles (vasodilation), which helps in reducing blood pressure.

Administration

Diazoxide is administered orally in the form of capsules for chronic conditions like insulinoma and intravenously for acute management of hypertensive crises.

Side Effects

Common side effects include:

• Fluid retention and edema
• Hyperglycemia (high blood sugar)
• Nausea and vomiting
• Increased heart rate
• Hyperuricemia (high levels of uric acid in the blood)

Serious side effects may include:

• Heart failure
• Excessive hair growth
• Low blood pressure

Contraindications

Diazoxide should not be used in patients with:

• Hypersensitivity to diazoxide or any component of the formulation
• Compensatory hypertension
• Pulmonary hypertension

Pharmacokinetics

Diazoxide is well absorbed after oral administration but has a high first-pass metabolism, which reduces its bioavailability. It is highly protein-bound and has a half-life that allows for twice or thrice daily dosing in most cases.

Interactions

Diazoxide can interact with other medications, such as:

• Diuretics, which can exacerbate fluid retention
• Drugs that lower blood sugar, as diazoxide can counteract their effects
• Antihypertensive drugs, which may have additive effects with diazoxide, leading to excessive blood pressure reduction

See Also

• Insulinoma
• Hypoglycemia
• Hypertension
• Potassium channel opener