Objective—To determine pharmacokinetics and tissue
concentrations of azithromycin in ball pythons
( Python regius ) after IV or oral administration of a single
Animals—2 male and 5 female ball pythons.
Procedures—Using a crossover design, each snake
was given a single dose of azithromycin (10 mg/kg) IV.
After a 4-week washout period, each snake was given
a single dose of azithromycin (10 mg/kg) orally. Blood
samples were collected prior to dose administration
and 1, 3, 6, 12, 24, 48, 72, and 96 hours after
azithromycin administration. Azithromycin was quantitated
by use of liquid chromatography-mass spectrometry.
Results—After IV administration, azithromycin had an
apparent volume of distribution of 5.69 L/kg and a
plasma clearance of 0.19 L/h/kg. Harmonic means for
the terminal half-life were 17 hours following IV
administration and 51 hours following oral administration.
Mean residence times were 37 and 94 hours following
IV and oral administration, respectively.
Following oral administration, azithromycin had a peak
plasma concentration (Cmax) of 1.04 µg/mL, a time to
Cmax of 8.4 hours, and a prolonged mean absorption
time of 57 hours. Mean oral bioavailability was 77%.
Tissue concentrations ranged from 4 to 140 times the
corresponding plasma concentration at 24 and 72
hours after azithromycin administration.
Conclusions and Clinical Relevance—Azithromycin
is well absorbed and tolerated by ball pythons. On the
basis of plasma pharmacokinetics and tissue concentration
data, we suggest an azithromycin dosage in
ball pythons of 10 mg/kg, orally, every 2 to 7 days,
depending upon the site of infection and susceptibil
ity of the infective organism. (Am J Vet Res 2003;64:225–228)