METABOLIC EFFECTS OF THE STEROID ANTIBIOTIC FUSIDIC ACID

Hepatotoxicity and hematologic complications induced by fusidic acid in a patient with hepatitis B cirrhosis: A case report

RATIONALE

Fusidic acid (FA) is an active agent against gram-positive bacteria such as Staphylococcus, it is generally well tolerated and the major adverse effects are mild gastrointestinal discomfort, diarrhea, and headache. However, some rare side effects such as granulocytopenia and thrombocytopenia have also been reported. Here we report a case of FA-induced hepatotoxicity and hematologic toxicity.

PATIENT CONCERNS

A 54-year-old woman with hepatitis B cirrhosis was referred to us because of fever, Staphylococcus aureus was identified in the twice blood culture, and intravenous FA was given (0.5 g, q8 hours). Twelve days after FA therapy, she developed nausea and jaundice. Meanwhile, complete blood cell count showed neutropenia (white blood cell count of 1360/μL, neutrophil of 619/μL) and aggravated thrombocytopenia (platelet count of 18,000/μL). Adverse drug reaction was suspected, and FA was stopped immediately, after 1 day of discontinuation of FA, nose bleeding occurred and the platelet count declined further and reached the lowest value of 4000/μL.

DIAGNOSES

Hepatotoxicity and hematologic complications induced by FA were diagnosed.

INTERVENTIONS AND OUTCOMES

The FA was stopped immediately, and concentrated platelet transfusion was used. Five days after withdrawal of FA, jaundice resolved and the hematologic index returned to the level before the medication.

LESSONS

Hematologic adverse effect accompanying with hepatotoxicity may be induced by FA. Though the risk is rather low, it should not be overlooked.

Fusidic acid adverse drug reactions

Unlike trials conducted today on new antimicrobials, the introduction of fusidic acid was not accompanied by extensive studies on toxicity and side effects. The early studies on small numbers of patients reported fusidic acid to be a nontoxic drug with the main side effects being gastrointestinal tract discomfort, diarrhoea and headache. Case reports of hepatotoxicity were reported from 1972. A retrospective analysis showed this to be reversible and mainly associated with intravenous administration. Rarely reported side effects are granulocytopenia, thrombocytopenia and venous spasm. Skin reactions, including contact dermatitis, are uncommon. After many years of use the most common side effects reported for fusidic acid are minor and relate to the gastrointestinal tract.

Anti-tumor necrosis factor properties of non-peptide drugs in acute-phase responses

Dexamethasone (sodium phosphate), pentoxifylline, fusidic acid (sodium salt), pentamidine (isethionate) and R-phenylisopropyladenosine (R-PIA) were tested for their anti-tumor necrosis factor (TNF) activities in an endotoxin-induced shock rat model. All the drugs reduced serum TNF concentrations in a dose-dependent manner, whereas their effects on serum interleukin-6 levels differed. Doses that reduced TNF levels by 50% were 0.012 mg/kg for dexamethasone, 0.06 mg/kg for R-PIA, 0.24 mg/kg for pentamidine, 6.5 mg/kg for fusidic acid and 15 mg/kg for pentoxifylline. Administration of the drugs to rats before intraplantar injection of carrageenan reduced paw edema by 50-70%. Injection of a monoclonal anti-TNF antibody reproduced the inhibitory effect. Moreover, the time course of tissue-associated TNF following carrageenan injection was compatible with mediation of edema by TNF. Results obtained for this acute, non-immunological inflammatory reaction strongly suggest that the model is TNF-dependent. Our results reinforce the idea that TNF is a crucial target in the therapeutics of inflammatory reactions. These drugs, which are able to cross cell barriers, might have clinical applications in localized and/or chronic diseases in which TNF is involved.

Fusidic acid-induced hyperbilirubinemia

A 72-year old man developed jaundice while on fusidic acid therapy for suspected osteomyelitis. Hyperbilirubinemia was predominantly of the conjugated variety and elevation in liver enzymes was mild and transient. Although serum bilirubin fell rapidly after fusidic acid was stopped, complete resolution of the hyperbilirubinemia took nearly a month. Other possible causes of jaundice were excluded. Light microscopy of a needle liver biopsy showed focal hepatocyte feathery degeneration, intracellular bile retention, and canalicular bile plugging, most prominent in perivenous regions. Electron microscopy revealed varying degrees of canalicular dilatation, loss of microvilli, and disruption of the canalicular membrane with vesicular bleb formation as well as canalicular bile plugs. Widening of the pericanalicular ectoplasmic zone with accumulation of cytoskeletal filaments was also noted. These findings are similar to those reported in experimental cholestasis induced by bile acids. Possible mechanisms of jaundice caused by fusidic acid are discussed.

Effect of fusidic acid on the immune response in mice

The effect of fusidic acid on the immune response in mice was studied. At the nontoxic dose of 500 mg/kg per day, the cell-mediated immunity was strongly inhibited. A marked and significant prolonged survival of split-heart allografts in treated animals was detected. The survival time of allografts in mice receiving fusidic acid from the day of the transplantation until the grafts were rejected was 26.1 days compared with 14.5 days in untreated animals. In mice treated also before the transplantation, the mean survival of the allografts were even longer. The phytohemagglutinin response, as well as the mixed lymphocyte culture stimulation of spleen lymphocytes from mice given 500 mg of fusidic acid per kg daily for 1 week, were significantly inhibited. At the same dose there was also a significantly decreased primary antibody response to sheep erythrocytes, but it was of limited biological significance. The immunosuppressive effect in animals treated with a human therapeutic dose of fusidic acid (25 mg/kg per day) was less pronounced but significant. The relevance of these results is discussed.

Fusidic acid: new opportunities with an old antibiotic

The extensive foreign experience with fusidic acid prior to its belated introduction to Canada is reviewed. Fusidic acid is a steroid antibiotic with minimal toxic and hormonal effects that is mainly excreted through the liver. It has a predominantly bactericidal action and does not shown cross-resistance with other antibiotics. Since organisms resistant to this drug form easily in vitro when exposed to low concentrations, complementary treatment with another antibiotic may be required in some clinical situations. Although fusidic acid is active in vitro against a number of organisms, to date it has mainly been used to treat serious infections due to Staphylococcus aureus. The agent appears to be particularly valuable in the treatment of bone and joint infections and in pediatric practice. Fusidic acid will soon be available in Canada for both oral and intravenous administration. Attainable antibiotic levels in many tissues and body fluids greatly exceed the minimum inhibitory concentrations.

Antibiotics and suppression of lymphocyte function in vitro

The effects on the mitogenic response of human T lymphocytes were studied for 20 different antibiotics. No apparent inhibitory effect could be detected for penicillins, cephalosporins, aminoglycosides, chloramphenicol, sulfamethoxazole, trimethoprim, nalidixic acid, and 5-fluorocytosine. There were effects at high concentrations with erythromycin, clindamycin, and rifampin, and these antibiotics could also be shown to depress the mitogenic response of B lymphocytes. With fusidic acid, nitrofurantoin, and doxycycline there was an inhibiting effect at low concentrations on the mitogenic responses of B and T lymphocytes and on in vitro antibody production. Protein synthesis in unstimulated lymphocytes was also inhibited. Some antibiotics thus may impair the function of human lymphocytes in vitro.

Effects of cloxacillin, doxycycline, fusidic acid and lincomycin on the mechanical properties of bone and skin in young rats

The influence of cloxacillin, doxycycline, fuside acid and lincomycin on the mechanical properties of bone and skin in young rats was examined. The concentrations of the antibiotics in plasma corresponded to therapeutic levels in man. After 14 days of medication the weights of the rats receiving cloxacillin or doxycycline were significantly less when compared with the controls. The doxycycline, the fusidic acid and the lincomycin treated rats had reduced longitudinal growth of femur and reduced tensile strength of intact skin. No differences between any of the antibiotic groups and the control group were found in the tensile strength of incisional skin wounds or in the mechanical properties of the femur and tibia.

Antibacterial drugs today. I

Since the development of the sulphonamides in the 1930s and the subsequent development of antibiotics from the 1940s onwards, there have now been many drugs developed which are capable of chemotherapeutic activity in a patient infected by a susceptible micro-organism. This review is concerned with precise descriptions of important groups of antimicrobial drugs, with emphasis being placed on the more recently developed drugs. With each group of drugs the pharmacology, major therapeutic indications, dosages and adverse reactions are discussed. Part I of the article discusses the sulphonamides, the natural and semi-synthetic penicillins, cotrimoxazole, chloramphenicol, tetracyclines, the macrolides, lincomycin and clindamycin, fusidic acid, and the urinary antiseptics. The place of each in therapy is defined.