What is a positive clonidine suppression test?
Using the first criterion for diagnosis in which the clonidine suppression test is positive when the plasma noradrenaline is >2.96 nmol l–1 at 3 h gave a sensitivity of 87% (13/15 patients) and a specificity of 95% (39/41) (Figure 1).
Which of the following results is indicative of pheochromocytoma during clonidine suppression test?
Baseline plasma norepinephrine (NE) and epinephrine (E) levels over 2000 pg/ml or failure to suppress to less than 500 pg/ml after oral clonidine have been considered diagnostic of the presence of a pheochromocytoma.
What test is confirmatory of pheochromocytoma?
The most commonly ordered blood test for pheochromocytoma is the plasma free metanephrine test. Though more convenient to obtain than a 24-hour urine collection, plasma free metanephrine testing is plagued by frequent false positive results.
How long does clonidine stay in urine?
Clonidine crosses the placental barrier. It has been shown to cross the blood-brain barrier in rats. Following oral administration about 40% to 60% of the absorbed dose is recovered in the urine as unchanged drug in 24 hours.
What is a Metanephrine test?
What is a plasma metanephrine test? It’s a test to help diagnose a condition of the adrenal glands. These are found at the top of the kidneys and are responsible for producing the hormones adrenaline and noradrenaline, which are required for the normal working of the body.
How long does clonidine stay in your system for a drug test?
Based on its half-life, clonidine stays in your system for about 2.5 to 3.5 days after taking a dose.
How long does clonidine stay in the system?
Based on its half-life, clonidine stays in your system for about 2.5 to 3.5 days after taking a dose. Its levels will gradually decrease over this time. If you have other questions about how long the effects of clonidine last, talk with your doctor or pharmacist.
When is clonidine out of system?
Its peak concentration in the blood occurs 2 to 4 hours post-ingestion, and its half-life is between 5 and 13 hours. Half the administered dose is excreted unchanged in the urine.
When to use a stimulatory test for clonidine suppression?
Its accuracy diminishes in patients with low baseline plasma catecholamine levels, who may better be tested with a stimulatory test (ie, glucagon). The use of diuretics, β-blockers, and antidepressants may cause false-positive results or severe hypotension during the clonidine suppression test.
When to use the clonidine suppression test for pheochromocytoma?
In those patients with a plasma norepinephrine of less than 2000 pg/mL, the clonidine suppression test is 92% accurate in diagnosing pheochromocytoma when the normal response to clonidine is defined as total plasma catecholamines of less than 500 pg/mL.
Are there any drugs that interfere with clonidine suppression?
Clonidine Suppression. The α-adrenergic blocking agents do not interfere with clonidine suppression. Drugs that may affect plasma norepinephrine levels include α-adrenergic and β-adrenergic blockers, vasodilators, clonidine, bromocriptine, theophylline, phenothiazine, tricyclic antidepressants, labetalol, calcium channel blockers,…