Behavioral comparison of the oximes TMB-4, 2-PAM, and HI-6 in rats using operant conditioning

Behavioral side effects of prophylactic therapies against soman-induced seizures and lethality in rats

Four medical therapies previously shown to exert varying degrees of protection against a convulsant dose of soman were assessed for potential behavioral side effects in a novelty test. In Experiment 1, HI-6 (1-[([4-(aminocarbonyl)pyridino] methoxy)methyl]-2-[(hydroxyimino)methyl]pyridinium) (125 mg/kg), scopolamine (1 mg/kg), physostigmine (0.1 mg/kg), levetiracetam (50 mg/kg), and procyclidine (20 mg/kg) were tested separately. In Experiment 2, the combination of HI-6, scopolamine, and physostigmine (termed the physostigmine regimen) or HI-6, levetiracetam, and procyclidine (termed the procyclidine regimen) were tested. In Experiment 3, the metabotropic glutamate modulators DCG-IV ((2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine) (4 mg/kg) and MPEP (2-Methyl-6-(phenylethynyl)pyridine hydrochloride) (30 mg/kg) were tested separately or each drug in combination with HI-6 and procyclidine (termed the DCG-IV regimen and the MPEP regimen, respectively). The results showed that the physostigmine and procyclidine regimens both produced severe cognitive impairment (lack of preference for novelty) and reduced locomotor and rearing activities. The DCG-IV and MPEP regimens caused milder deficits on the same behavioral measures. Some relations were seen between prophylactic capacity and degree of behavioral side effects. Only HI-6 or levetiracetam had no adverse effects on behavior. DCG-IV or MPEP produced some impairment, whereas the detrimental effects of scopolamine or procyclidine were pronounced. The relatively high dose of procyclidine (anticholinergic and antiglutamatergic) needed for prophylactic efficacy may have played a major role for the side effects of the regimens in which the drug was used. It was concluded that behavioral side effects are inevitable for potent prophylactic therapies against soman intoxication.

Pediatric poisoning from trimedoxime (TMB4) and atropine automatic injectors

OBJECTIVE

To describe the effects of combined trimedoxime (TMB4) and atropine poisoning from automatic injectors (AI) in children.

STUDY DESIGN

Data was collected from two sources: calls to the Israel Poison Information Center (IPIC) during a 1-year period and a cohort of children who presented to pediatric emergency departments (EDs) after unintentional injection of an AI. Demographic data and data regarding the type of AI, site and time of injection, and the clinical manifestations were abstracted.

RESULTS

Data were available for 142 patients. The median age was 8.5 years (range 1.25-18 years). The dose of atropine and TMB4 was higher than the recommended dose for age in 22 (15.5%) cases. There were few side effects attributable to atropine: dilated pupils (26.7%), dryness of mucous membranes (24.6%), and tachycardia (22.5%). Compared with children injected with an age-appropriate dose, children injected with an AI that contained a dose that exceeds the recommended one were more likely to be symptomatic ( P = .029). There were no side effects characteristic to oximes, and no specific medical intervention was required.

CONCLUSIONS

Unintentional pediatric atropine and TMB4 injection, even an adult dose in a small child, does not cause significant side effects.