Sorted By Test Name - Mayo Medical Laboratories

FFTIK
91818
TICKS
83265
Useful For: This test is used for monitoring tiagabine therapy. Because tiagabine has a wide
therapeutic index and dose-dependent toxicity, routine drug monitoring is not indicated in all patients.
Drug monitoring is indicated when initiating concomitant therapy with antiepileptic drug that induce
hepatic enzymes and when the patient does not respond to treatment to ascertain whether treatment failure
is due to noncompliance or nonresponse to the drug.
Interpretation: Trough tiagabine serum concentrations are in the range of 5 to 35 ng/mL in most
patients receiving therapeutic doses. Tiagabine serum concentration is proportional to dose.(2,8) A single
4-mg dose administered to a child produced peak serum concentration in the range of 52 to 108 ng/mL.(5)
At steady-state, an adult receiving 40 mg per day is expected to have peak serum concentration in the
range of 110 to 260 ng/mL, and an adult receiving 80 mg per day is expected to have peak serum
concentration in the range of 220 to 520 ng/mL. Serum concentrations >800 ng/mL indicates excessive
dosing associated with adverse effects such as asthenia, ataxia, difficulty concentrating, and depression. In
healthy adults administered tiagabine, steady-state peak serum concentrations within 1 hour of dosing are
typically in the following ranges:(2) -Peak serum concentration (4 mg q.i.d.): 36 to 92 ng/mL -Peak serum
concentration (8 mg q.i.d.): 72 to 184 ng/mL Pediatric patients (3-10 years) reach peak concentration at
approximately 2.4 hours.(5)
Reference Values:
Peak: 110-520 ng/mL
Trough: 5-35 ng/mL
Clinical References: 1. Product information: Gabitril Filmtab, tiagabine hydrochloride. Abbott
Laboratories, North Chicago, IL, 1997 2. So EL, Wolff D, Graves N, et al: Pharmacokinetics of tiagabine
as add-on therapy in patients taking enzyme-inducing antiepilepsy drugs. Epilepsy Res 1995;22:221-226
3. Benedetti MS: Enzyme induction and inhibition by new antiepileptic drugs: a review of human studies.
Fundam Clin Pharmacol 2000;14:301-319 4. Perucca E: The clinical pharmacokinetics of the new
antiepileptic drugs. Epilepsia 1999;40:S7-S13 5. Gustavson LE, Soellner SW, Granneman GR, et al: A
single-dose study to define tiagabine pharmacokinetics in pediatric patients with complex partial seizures.
Neurology 1997;48:1032-1037 6. Cato A, Gustavson LE, El-Shourbay, Kelly EZ: Effect of renal
impairment on the pharmacokinetics and tolerability of tiagabine. Epilepsia 1998;39:43-47 7. Wiley Cl,
Enger RJ, Charlson JC, Moyer TP: Unpublished Mayo information 8. Thompson MS, Groes L, Agerse H,
Kruse T: Lack of pharmacokinetic interaction between tiagabine and erythromycin. J Clin Pharmacol
1998;38:1051-1056
Tick Analysis and Identification by PCR B. burgdorferi
Reference Values:
Negative
Test Performed By: IMUGEN Reference Diagnostic Division
315 Norwood Park South
Norwood, MA 02062
Tick-Borne Disease Antibodies Panel, Serum
Clinical Information: In North America, ticks are the primary vectors of infectious diseases.(1)
Worldwide, ticks rank second only to mosquitoes in disease transmission. In the United States, tick-borne
diseases include Lyme disease, Rocky Mountain spotted fever, human monocytic and granulocytic
ehrlichiosis, babesiosis, tularemia, relapsing fever, and Colorado tick fever. Symptoms of the various
tick-vectored diseases range from mild to life-threatening. Early symptoms, which include fever, aches,
and malaise, do not aid in distinguishing the various diseases. Because early treatment can minimize or
eliminate the risk of severe disease, early detection is essential, yet patients may not have developed
distinctive symptoms to help in the differential diagnosis. A tick-borne panel can assist in identifying the
pathogen, allowing treatment to be initiated. For information on the specific diseases, please see the
individual unit codes.
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