I got this from the Canine Liver Health group and thought it might be helpful to some...
The following is about Antibiotic Therapy for treating liver disease
But it does NOT mention the possible adverse
side effects that Flagyl can have on the liver
, and we know this is
true. So not sure how helpful it is other than showing what
antibiotics are most often prescribed for dogs with known liver
Antibiotic therapy is indicated for treatment of suppurative
hepatitis, cholangiohepatitis and hepatic encephalopathy, and
prevention of septicemia. The bactericidal function of the hepatic
reticuloendothelial (RE) system may be compromised in hepatic
disease, especially if hepatic blood flow or oxygen tension is
altered, resulting in septicemia.
In hepatic bacterial
encephalopathy, antibiotics are used to help reduce colonic bacterial
numbers in an effort to decrease ammonia formation. Cholangitis has
several causes, including bacterial invasion, which warrants
antibiotic therapy. The regimen may be modified in accordance with
specific information obtained from cultures of bile, hepatic tissue
or blood. In cases of compromised hepatic RE function (e.g. hepatitis
from any cause, septicemia) the antibiotics selected generally are
directed against intestinal organisms.
Antibiotics routinely used in treatment of patients with liver
disease include penicillins (ampicillin 10 mg/lb TID, amoxicillin 10
mg/lb BID), cephalexin (Keflex, Dista) 10 mg/lb TID, enrofloxacin
(Baytril) 1.2 - 2.3 mg/lb BID, and metronidazole (Flagyl, Searle) 5- 10 mg/lb BID.
Chloramphenicol and tetracycline are alternative
choices that are effectively excreted in the bile, however,
tetracycline is potentially hepatotoxic. Although high hepatic tissue
levels are reached with chloramphenicol, the plasma half-life can be
prolonged and toxicity may occur in patients with liver disease.
Metronidazole is highly active against Bacteroides and other
anaerobes that exist in high numbers in the colon. Bacteriologic
studies have suggested that gram-negative anaerobes are major
generators of ammonia from peptides. Metronidazole's effectiveness
against these bacteria could help reduce production of endogenous
ammonia, thus benefiting patients with hepatic encephalopathy. It may
also be useful in treatment of any liver disorder complicated by
inability of the hepatic RE system to clear bacteria absorbed through
the portal circulation.
The combination of metronidazole and an
aminoglycoside may be superior for this purpose. Metronidazole may
also be useful in treatment of some chronic inflammatory conditions
because it helps reduce cell-mediated immune responses. I sometimes
use metronidazole for 2-6 months or longer, in conjunction with
maintenance levels of corticosteroids, for liver disease patients
that may have both a bacterial and inflammatory component, or that
are unable to tolerate required dosage levels of corticosteroids used
alone to control the disease. Metronidazole is my routine drug of
choice for chronic administration in hepatic encephalopathy patients.
It can be used safely in combination with other antibiotics.
Antibiotics that should be avoided in treatment of liver disease
include chloramphenicol, lincomycin, sulfonamides, erythromycin, and
hetacillin. These drugs are either inactivated by the liver, require
hepatic metabolism, or are capable of producing hepatic damage.
If septicemia or peritonitis occurs in conjunction with liver disease
gentamicin 1 mg/lb TID IM or SC is administered for 5-7 days (while
monitoring renal function carefully) in conjunction with cephalothin
(Keflin, Lilly) at 10 mg/lb TID IV or cefoxitin (Mefoxin) at 10 mg/lb
TID to QID IV for broad-spectrum coverage while awaiting culture and
sensitivity results. If an anaerobic organism is identified on
culture the antibiotics most likely to be effective include
penicillin G 10,000 u/lb every 4-6 hours IV, metronidazole, or
clindamycin 2.5-5 mg/lb BID PO."