Human exposures to tilmicosin reported to poison centres, Texas, 1998-2003

Tilmicosin, or 20-deoxo-20-(3,5-dimethylpiperidin-1-yl)desmycosin, is a macrolide antibiotic primarily utilized in livestock. This study examined 46 human exposure calls involving tilmicosin received by Texas poison centres during 1998 - 2003. The majority (91%) of the calls were received from northern and central Texas. All of the cases were unintentional exposures. The most frequent route of exposure was parenteral (48%). The majority of the patients were males (80%) and adults (84%). Only 46% of the patients were managed outside of health care facilities. Some sort of adverse medical outcome was reported in 93% of parenteral exposures and 54% of other-route exposures. However, only 21% of parenteral exposures and 15% of other-route exposures involved medical outcomes that were judged to be moderate or worse. No deaths were reported. The most frequently reported clinical effects among parenteral cases were dermal (79%), while only 9% of other-route exposures had dermal effects. Cardiovascular clinical effects were observed in a single case of parenteral exposure and a single case of other-route exposure. Although the majority of cases were managed with the assistance of health care facilities, the medical outcomes were usually not serious. Outcome depended on the route of exposure.

Analysis of reports of human exposure to Micotil 300 (tilmicosin injection)

OBJECTIVE

To identify clinical signs associated with and outcome of human exposure to Micotil 300 (tilmicosin injection).

DESIGN

Retrospective case series.

STUDY POPULATION

Reports of 3,168 human exposures to Micotil 300.

PROCEDURES

Reports of human exposure to Micotil 300 submitted to the Elanco Animal Health Pharmacovigilance Unit between March 1992 and March 2005 were reviewed.

RESULTS

At least 1 clinical sign was described in 1,404 (44%) reports, whereas the remaining 1,764 (56%) exposures were presumably asymptomatic. Eighty percent of exposures involved males; mean age was 38 years. Sixty-one percent of exposures were a result of accidental injection, with injection site pain, bleeding, swelling, or inflammation being the most common signs, followed by nausea, tachycardia, dizziness, anxiety, an abnormal taste, headache, lightheadedness, limb pain, paresthesia, chest pain, and soreness. Only 156 (5%) reports involved serious adverse effects (ie, tachycardia, bradycardia, hypertension, hypotension, heart disorder, chest pain, tachypnea, or death). There were reports of 13 deaths following tilmicosin exposure, but only 2 of those deaths were related to accidental exposure. Time to onset of clinical signs was < or = 60 minutes in 63 of the 156 (40%) reports involving serious adverse effects.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that the overall risk of accidental human exposure to tilmicosin resulting in serious adverse effects is low (approx 2 people for every 1 million doses administered). Nevertheless, safe handling and proper use should be emphasized.

Clinical presentation and management of moxidectin toxicity in two dogs

Moxidectin is a macrocyclic lactone related to ivermectin used in horses and dogs for endoparasite treatment and prophylaxis. The clinical and neurological presentation of moxidectin toxicity in two dogs following inadvertent poisoning with a moxidectin-containing equine de-worming medication is reported here. In both the dogs, the predominant clinical signs were generalised tremors and ataxia. Moxidectin exerts its neurotoxic effects in mammals by potentiating the effect of gamma-aminobutyric acid and, consistent with this, both the dogs demonstrated a poor response to treatment with diazepam. It would be more appropriate to avoid gamma-aminobutyric acid agonists, such as benzodiazepines and barbiturates, in dogs with moxidectin toxicity and consider using anaesthetic agents with a different mode of action, such as propofol. The prognosis in dogs accidentally exposed to moxidectin-containing equine de-worming medication appears to be excellent if the cause of the neurotoxicity is correctly identified and the case is appropriately managed.

Presumed moxidectin toxicosis in three foals

Outcome and complications associated with administration of moxidectin gel to 3 foals < 4 months old are described. Two foals became comatose but survived following supportive treatment. One foal died following loss of consciousness associated with moxidectin administration. Risk of moxidectin overdose exists, because horse owners often fail to read or comprehend the package insert instructions pertaining to use of the syringe-locking mechanism. In addition, moxidectin should not be administered to foals < 4 months old, because it is likely that treated foals will become comatose.