Comparative pharmacokinetics of oral versus sublingual clonidine.
OBJECTIVE
To compare the pharmacokinetic and pharmacodynamic profile of orally versus sublingually administered clonidine.


METHODS
Randomized, crossover, nonblinded, open-label study.


METHODS
University tertiary-care center.


METHODS
10 healthy male and female volunteers aged 20 to 42 years.


METHODS
A heparinized catheter was placed intravenously for blood-sampling purposes. An automatic sphygmomanometer was placed on the volunteers' left upper arm to obtain systolic and diastolic blood pressure, and a pulse oximeter was placed on the right index finger to measure heart rate (HR).


RESULTS
Serial blood samples were collected throughout the 24-hour study period to determine clonidine concentrations. The effect of clonidine on blood pressure (BP) and HR also was measured. The half-life, area under the curve, maximum concentration, and time to reach maximum concentration were similar for both the sublingual and oral routes. BP and HR changes were similar for both sublingual and oral clonidine.


CONCLUSIONS
Both routes of administration resulted in similar pharmacokinetic and pharmacodynamic profiles. Attempts to shorten clonidine's latency with sublingual administration were unsuccessful. Our study shows that a single dose of clonidine 0.3 mg has the same pharmacokinetic and dynamic profile when administered orally or sublingually. Therefore, the sublingual route can be predictably used in fasting patients, those having difficulty swallowing, or those who are unable to absorb drugs through the gastrointestinal tract; the sublingual dose is the same as the oral dose.
Cunningham
F E
FE
Department of Anesthesiology, University of Illinois College of Medicine, Chicago.
Baughman
V L
VL
Peters
J
J
Laurito
C E
CE
D000284:Administration, Oral; D000286:Administration, Sublingual; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D003000:Clonidine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D005260:Female; D006207:Half-Life; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate
D003000:Clonidine