None listed
Conditions
Brief summary
Quetiapine is a commonly-prescribed drug with a good safety margin that is prescribed in psychotic illnesses, agitation and anxiety. Thyroid function is commonly checked in patients with psychotic disorders and signs of anxiety. We have observed that some patients taking quetiapine have low results on measure of free thyroid hormone level in blood, even though there is no other evidence that their thyroid function is impaired. We suspect this is because the quetiapine is interfering with the laboratory test, but it might actually be a biological effect of the quetiapine and potentially important to quetiapine’s adverse effects on metabolism. We are asking 20 patients in whom their treating psychiatrist has already made the clinical decision to commence quetiapine as part of their management plan, to provide us with a specimen of blood to check thyroid function on 4 occasions (prior to quetiapine commencement, 1 day following commencement of quetiapine, and at weeks 3 and 6 ). We will firstly check to see whether our impression, that free thyroid hormone tests are reading lower in patients on quetiapine by the current test, is correct. The current test is an immunoassay. Then we will use the same blood specimens to measure free thyroid hormone level by another newer, highly specific test (LCMSMS) that is not open to interference in the way immunoassays may be. A comparison of the results will tell us whether the problem is simply immunoassay interference from quetiapine.
Interventions
Collection of 4 blood specimens from 20 people who are about the start quetiapine and who are expected to continue treatment for at least 6 weeks. During this time, participants will take quetiapine according to their treating doctor's prescription. Doses will not be changed for the purposes of this study. The first specimen is collected before the first dose of quetiapine, then further specimens at day 1, week 3 and week 6.
Each specimen will be 7.5 millilitres, or about one and a half teaspoon
Collection of 4 blood specimens from 20 people who are about the start quetiapine and who are expected to continue treatment for at least 6 weeks. During this time, participants will take quetiapine according to their treating doctor's prescription. Doses will not be changed for the purposes of this study. The first specimen is collected before the first dose of quetiapine, then further specimens at day 1, week 3 and week 6. Each specimen will be 7.5 millilitres, or about one and a half teaspoons volume. Thyroid function and quetiapine will be measured in the specimens.
Sponsors
PathWest Laboratory Medicine
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
20 patients who are about to start taking quetiapine on a daily basis, and who are expected to still be taking it in 6 weeks time. Patients taking quetiapine for any indication may be recruited.
Exclusion criteria
No exclusion criteria
Outcome results
None listed