IS THE FDA COMFORTABLE
WITH LONG TERM ANTIBIOTICS?
Currently there is a battle between two organizations on how long you treat a patient with chronic Lyme disease. One organization is ILADS, which has physicians who have treated about 50-100,000 Lyme patients, and they strongly believe in longer treatment with antibiotics. Below, the FDA seems to be comfortable with long-term antibiotics in some conditions.
Safety of Long Term Therapy with Penicillin
and Penicillin Derivatives
December 6, 2001
MO: Chuck Cooper, MD
Safety of Long Term Penicillin and Penicillin Derivatives
The safety of penicillin and penicillin derivatives when administered either intramuscularly, intravenously, or orally for extended periods of time (beyond the usual duration of use) can be extrapolated from multiple published studies. A review of the medical literature reveals studies in which such drugs have been used therapeutically for extended treatment durations. This includes studies of the treatment of recurrent acute otitis media, endocarditis, salmonella infections, prophylaxis of at risk populations (asplenic children, young children with sickle cell disease, patients with prior rheumatic fever), and the long term treatment of certain types of Lyme disease. Although most of these studies focus primarily on efficacy, they do routinely contain general statements indicating the safety and tolerability of the treatment under study. A few studies mentioned the presence of isolated cases of rash, gastrointestinal events, but none of the studies report the occurrence of a serious adverse event.
A review of the Adverse Event Reporting System (AERS) database as performed by an Office of Post-Marketing Drug Risk Assessment (OPDRA) special programmer revealed occasional cases of adverse events associated with the administration of long term penicillin therapy, however, these adverse events were consistent with the known adverse event profile of penicillin. OPDRA concluded that "no increase in or atypical adverse drug reactions were noted in the few cases involving long-term administration of oral or intramuscular penicillin G or V (all dosage forms)." This data is generated via isolated adverse event reports submitted to the FDA, and it may be difficult to determine the overall rates of adverse events in relation to treatment duration. A similar analysis is currently being performed by OPDRA for amoxicillin and Augmentin®.
There is a higher incidence of cholestatic or mixed cholestatic-hepatocellular patterns of liver injury associated with administration of Augmentin¨. This has been demonstrated by several published case reports. 8, 12, 14, 17, 20, 22, 24, 27, 28 Fatalities are very rare (on the order of one in several million) and similar hepatotoxicity is not thought to occur with amoxicillin administration. A study by Garcia-Rodriguez identified specific sub-populations who might be at increased risk for hepatotoxicity.10 These groups include older patients, and patients on long term therapy. The overall risk is still very low but was noted to be significantly higher than for the comparison group receiving amoxicillin. The information from this study was submitted in a labeling supplement and resulted in the identification of these risk groups in the label.
These antibiotics have an extensive history of use, and the lack of any serious adverse events as reported in these studies support their reputation as safe drugs. Reassurance can be derived from the fact that no increase in serious adverse events has been reported in the literature despite broad usage. Clinicians should still be aware that, although quite unlikely, when using these drugs over extended period of time, the potential exists for slight increases in the rates of specific adverse events which are infrequent enough to have escaped detection. Although there is no data to suggest such an increase (except for Augmentin¨ and hepatotoxicity), adverse events could include increased liver function tests, serum sickness, interstitial nephritis, effects on anti-coagulant therapy, and neutropenia.
This is just a small excerpt from the FDA.
It is fully available for free at the FDA web site: www.fda.gov/cder/drugprepare/penlongsafety.htm