The objective of this study is to determine safety and characterize pharmacokinetics of higher doses of intravenous baclofen in healthy subjects. Thirty-six healthy adults received a single dose of PO baclofen (10mg, 15mg or 20mg) and a 10-minute infusion of IV baclofen (7.5mg, 11.5mg or 15mg respectively) with a minimum 48-hour wash out period. Twelve subjects also received a 60-minute infusion of 15mg IV baclofen following an additional 48-hour wash out period. The pharmacokinetic and tolerability information gained from this study will support the development of further studies to assess the use of IV baclofen to prevent or treat baclofen withdrawal syndrome.
This randomized, open-label, dose escalation, crossover study was conducted at a contract clinical research facility. Three single doses were evaluated using three cohorts (N=12 per cohort). Study doses were as follows: cohort 1 - 7.5mg IV and 10mg PO, cohort 2 - 11.5mg IV and 15mg PO, and cohort 3 - 15mg IV and 20mg PO. The IV baclofen doses for this trial were based on a 75% bioavailability observed in a previous low dose study.16 The oral formulation of the study drug used in this trial was 10mg baclofen tablet (Teva Pharmaceutical Industries Ltd.) and is commercially available. The intravenous formulation was 2mg/mL solution manufactured by Aptuit LLC. for this study. IV infusions were administered over 10 minutes. In addition, cohort 3 received 15mg over a 60-minute infusion. There was a minimum 48-hour washout period between doses. Initially, 3 subjects received study drug at a given dose, after assessing the safety and tolerance of baclofen the additional 9 subjects received study drug.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
39
University of Minnesota
Minneapolis, Minnesota, United States
Safety assessments
Blood Pressure \& Pulse: Recorded every 5 minutes immediately prior to, and during the IV infusion, then every 15 minutes for 1 hour, then every hour for 12 hours. Assessment of sedation / sleepiness: Subjects will be assessed by using the sleepiness scale prior to drug administration then every 30 minutes for four hours after drug administration. Ataxia and nystagmus: Measured using the following rating scale and definitions of ataxia and nystagmus. 0=none, 1=mild, 2=severe Ataxia: For those who are ambulatory, this will be assessed by gait. Ratings will be: mild-unsteady with tandem gait testing, but able to perform without assistance severe-unable to perform gait testing without assistance. For non-ambulatory subjects, ataxia will be assessed by finger to nose and finger pursuit maneuvers. Nystagmus: mild-present on extreme gaze; severe-present on midline gaze
Time frame: Upto 24 hours following drug administration
Maximum Concentration(Cmax)
Cmax: Cmax is the maximum baclofen concentration observed
Time frame: Upto 24 hours following drug administration
AUC(0-inf)
AUC(0-inf): Area under the plasma concentration-versus-time curve from time zero to infinity
Time frame: Upto 24 hours after drug administration
Plasma Decay Half-life (T1/2)
Plasma Decay Half-life(T1/2): Plasma decay half-life is the time measured for the plasma concentration to decrease by one half
Time frame: Up to 24 hours after drug administration
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