Tolerance study in cats on meloxicam
(Metacam) at dose levels of 0.3 and 0.6 mg/kg body
weight given as single subcutaneous injections followed by oral
treatment of the same dosages
for 9 consecutive days
Twelve adult cats, six males and six females, were randomly
allocated to three equal groups. Group 1
received a single s.c. injection of placebo on day 0, followed by
daily oral placebo dosing for 8 days.
Groups 2 and 3 were given s.c. injections of 0.3 and 0.6 mg/kg b.w.,
respectively, on day 0 followed by oral administration of the same
doses for 8 days.
The study was originally designed for a treatment period of 10
days, but 2 cats, one in group 2 and one in group 3, were found dead
on day 8.
These animals had shown depressed demeanour and reduced appetite
since days 3-4 of the study.
After 8 days of treatment depressed demeanour and
gastrointestinal signs occurred in two cats in group 2 and in three
cats in group 3. On day 9 all
meloxicam treated animals showed clinical signs (animal more subdued
than normal), the study was
terminated and all surviving animals were necropsied.
Pyloric/duodenal ulceration and
peritonitis were
found in two cats of the highest dose group. Signs of peritonitis
were found also in the other two cats
of this group, but the pylorus/pyloric duodenal junction was not
investigated histologically in these
animals. Minimal signs of peritonitis occurred also in two animals
treated with 0.3 mg/kg b.w. over 8
to 9 days. Granulomatous inflammation of the intestinal wall was
found in one animal. Feline
Infectious Peritonitis was excluded by serological investigation.
Clinical signs of NSAID toxicity were a depressed demeanour and
gastrointestinal signs.
Pathohistological pyloric/duodenal ulceration and peritonitis were
described. No treatment related
haematological or blood chemical changes were found. Faeces was
tested for the presence of occult
blood during the study, and positive samples were found in all
groups (including placebo) at all time
points and also pretreatment. Similar experiences were recorded in
earlier dog studies, and the
conclusion was drawn that commercial kits for the testing of blood
in faeces are not reliable. The
findings of the study were that repeated administration of meloxicam
at the doses 0.3 and 0.6 mg/kg
b.w. followed by oral administration of the same doses for 8 days
can cause pyloric and duodenal
ulceration and that the risk/benefit needed to be evaluated at lower
dose levels. |