Tratamento da epilepsia idiopática canina - quadro clínico após interação medicamentosa / Treatment of canine idiopathic epilepsy - clinical picture after drug interaction

Background: The large number of diseases demand perennial development of the pharmaceutical industry. The drugtesting phase is essential to make them available safely. Awareness of pharmacological properties, adverse effects and drug interactions is required. Drug interactions are common in veterinary medicine and should be avoided. At times, epileptic seizures require polydrug therapy, predisposing patients to drug interactions. The interaction between carbamazepine and phenobarbital reported in the literature is an example. The aim of this paper is to report a clinical picture of drug interaction in the treatment of idiopathic epilepsy. Case: A 1-year-old Border Collie male dog, was admitted at the Veterinary Hospital of the Federal University of Lavras in post-ictal. The tutor reported that a year ago the animal had epileptic seizures and clusters with intervals of 21 to 25 days. Despite the continued use of previously prescribed phenobarbital (7.4 mg/kg, v.o., BID, until new recommendations) and carbamazepine (7.5 mg/kg, v.o., BID, until new recommendations), seizure control was not achieved. The physical examination indicated, tachypnea, ptialism, mydriasis, intense fatigue, and alienation from the environment. The patient did not respond to the threat-reflex test. Blood count, hepatic and renal blood chemistry, serum electrolyte (potassium, sodium, calcium and phosphorus), and phenobarbital dosages were requested. Based on the animal's history, breed characteristics, and alterations in the physical examination associated with normal results in complementary exams, idiopathic epilepsy was diagnosed. After analyzing the case, it was observed that the inefficiency in the control of seizures was possibly due to the drug interaction between phenobarbital and carbamazepine. Carbamazepine and phenobarbital reciprocally reduce their half-lives. To confirm the raised hypothesis, the serum concentration of carbamazepine was gradually reduced through weaning from its dose administered to the patient. Serial dosage of the concentration of phenobarbital in the bloodstream was performed. As a result, the serum phenobarbital, previously dosed at a concentration of 13.3 mg/dL with concomitant administration of carbamazepine, increased to 22 mg/dL 40 days after the beginning of weaning from carbamazepine (T0), and then to 36 mg/dL 100 days after T0. There was an increase in the concentration of phenobarbital in the bloodstream while the serum concentration of carbamazepine declined. The patient spaced out his seizures to every 50 to 60 days with phenobarbital monotherapy at a dose of 6 mg/kg. Discussion: Efficient control of clusters, such as the reduction of seizures by 50%, was only possible due to the meticulous perception of the possible interaction reported in medicine. Carbamazepine and phenobarbital are P450 isoenzyme inducers. The concomitant administration of both drugs potentiated the action of isoenzymes in the hepatic microsomal system, which led to an accelerated metabolic processing of the drugs. After weaning from carbamazepine, that is, reducing the action of carbamazepine on the isoenzymes of the P450 enzyme system, the concentration of phenobarbital normalized at 36 mg/ dL. Such concentration is within the reference range reported in the literature: 25 mg/dL to 35 mg/dL of serum phenobarbital for treatment efficacy. Therefore, the control of convulsive crises was achieved. The increase in the concentration of phenobarbital due only to weaning from carbamazepine, even after decreasing the daily dose of barbiturate prescribed to the animal, contributed to evidence of the interaction of these drugs. It is noted that prior knowledge of pharmacological properties, careful study of the patient's history, and the cooperation of the tutor were essential for the therapeutic success and practice of evidence-based veterinary medicine.

Megaesôfago em muar / Megaesophagus in mule

Background: Megaesophagus is a chronic dilation of the esophagus rarely found in horses. It’s a non-specific disease that is associated with several causes, and esophageal hypomotility is the dysfunction that most commonly results in organ dilation. In the literature, there are few reports of megaesophagus in horses and, to date, no cases in mule have been reported. The objective of this work is to describe a case of a donkey with thoracic megaesophagus. Case: A 16 year-old donkey, castrated male, mixed breed weighing 195 kg, was referred for clinical care with a history of 5 days of anorexia. On physical examination, apathy, cachexia, 8% dehydration, moderate enophthalmos, ptialism, bilateral nasal discharge, dry and bristling hair were observed. Due to the poor general condition, a nasogastric tube was chosen to perform enteral nutrition, however, it was not possible to progress the tube to the stomach. In order to confirm the suspicion of a possible esophageal obstruction, gastroscopy was performed, where it was possible to observe an esophageal dilation filled with bulky food located in the thoracic portion of the esophagus. In an attempt to stimulate esophageal motility, in order to promote the progression of the material present in the region of dilation, intramuscular metoclopramide was administered (two applications every 6 h), however the treatment had no effect. Due to the unfavorable prognosis and financial limitations of the owner, euthanasia was performed, which was followed by autopsy and histopathological examination. At necropsy, a marked dilation of the esophagus was observed in the thoracic portion, which was filled with approximately 500 grams of bulky food (grass). In the mucosa of this area...

Megaesôfago em muar / Megaesophagus in mule

Background: Megaesophagus is a chronic dilation of the esophagus rarely found in horses. Its a non-specific disease that is associated with several causes, and esophageal hypomotility is the dysfunction that most commonly results in organ dilation. In the literature, there are few reports of megaesophagus in horses and, to date, no cases in mule have been reported. The objective of this work is to describe a case of a donkey with thoracic megaesophagus. Case: A 16 year-old donkey, castrated male, mixed breed weighing 195 kg, was referred for clinical care with a history of 5 days of anorexia. On physical examination, apathy, cachexia, 8% dehydration, moderate enophthalmos, ptialism, bilateral nasal discharge, dry and bristling hair were observed. Due to the poor general condition, a nasogastric tube was chosen to perform enteral nutrition, however, it was not possible to progress the tube to the stomach. In order to confirm the suspicion of a possible esophageal obstruction, gastroscopy was performed, where it was possible to observe an esophageal dilation filled with bulky food located in the thoracic portion of the esophagus. In an attempt to stimulate esophageal motility, in order to promote the progression of the material present in the region of dilation, intramuscular metoclopramide was administered (two applications every 6 h), however the treatment had no effect. Due to the unfavorable prognosis and financial limitations of the owner, euthanasia was performed, which was followed by autopsy and histopathological examination. At necropsy, a marked dilation of the esophagus was observed in the thoracic portion, which was filled with approximately 500 grams of bulky food (grass). In the mucosa of this area...(AU)

Intoxicación por eslaframina en equino en la provincia de Santa Catarina / Slaframine intoxication in horse in Santa Catarina state / Intoxicação por eslaframina em equino no estado de Santa Catarina

Se relata un caso de intoxicación por eslaframina en equino, mestizo, macho, de siete años de edad, con peso de 400 kg, de utilización para tracción. El animal presentaba como señal clínico salivación excesiva, permaneció en área con formación por el trébol rojo (Trifolium pratense). Por la inspección del pastaje fueron observadas alteraciones en las hojas, compatibles con infección por Rhizoctonia leguminicola. La sospecha fue intoxicación por eslaframina, como tratamiento se fue retirado el animal de la pastaje de trébol rojo. Después de 24h el animal ceso el señal clínico de salivación excesiva, cuando se confirma el diagnóstico terapéutico.(AU)

A case of slaframine toxicosis has been reported in a seven year-old, half-breed horse weighing 400Kg, used for traction. The animal demonstrated excessive salivation as the clinical sign and it was maintained on a pasture with red clover (Trifolium pratense). Upon the inspection of the pasture, observed leaves changes compatible with infection by Rhizoctonia leguminicola. The suspicion was slaframine toxicosis, removal of the animal from the pasture with clover was indicated as treatment. The clinical sign stopped 24h after the feed had been withdrawn confirming the therapeutic diagnosis.(AU)

Relata-se um caso de intoxicação por eslaframina em um equino, mestiço, macho, de sete anos de idade, pesando 400 kg, utilizado para tração. O animal apresentava como sinal clínico salivação excessiva, permanecia em piquete formado de trevo vermelho (Trifolium pratense). À inspeção da pastagem foram observadas alterações foliares compatíveis com infecção por Rhizoctonia leguminicola. A suspeita foi intoxicação por eslaframina, e como tratamento o animal foi retirado da pastagem de trevo. Após 24h o animal cessou o sinal clínico de salivação excessiva, confirmando o diagnóstico terapêutico.(AU)

Efeitos das injeções epidurais de amitraz ou xilazina em vacas

O amitraz possui efeitos sistêmicos resultantes da atividade intrínseca com receptores adrenérgicos do tipo a-2. Nesse estudo, avaliaram-se os efeitos das injeções epidurais de amitraz (0,1 e 0,4 mg/kg), xilazina (0,05 mg/kg ) ou DMSO 10 % (5,0 mL) sobre a freqüência cardíaca (FC), pressão arterial sistólica (PAS), freqüência respiratória (FR), motilidade ruminal (MR), temperatura retal (TR), tônus do esfíncter anal (TEA), altura de cabeça (AC) e as latências da resposta a estímulos nociceptivos nas regiões da coxa (LECC) e coroa do casco (LRRM) de vacas. Houve redução da FC nos grupos amitraz e xilazina, sendo que nessa última a diminuição foi mais acentuada até os 65 minutos. A MR foi inibida nos grupos amitraz até os 240 minutos e xilazina até 180 minutos. Somente a xilazina reduziu a FR, PAS e AC. A LECC foi maior no grupo xilazina até os 240 minutos e no grupo amitraz (0,4 mg/kg) até os 120 minutos. A LRRM foi maior no grupo xilazina dos 15 aos 55 minutos. No grupo amitraz (0,4 mg/kg) o incremento dessa latência ocorreu entre 25 e 120 minutos. A TR aumentou dos 45 aos 210 minutos após tratamento com xilazina e diminuiu nos outros grupos. Houve relaxamento do esfíncter anal no grupo xilazina durante os 240 minutos. Houve diminuição do TEA do momento 35 ao 120 no grupo amitraz (0,4 mg/kg), quando comparado ao grupo DMSO. Salivação excessiva foi observada após tratamento com xilazina. Os animais dos grupos DMSO e amitraz (0,1 mg/kg) apresentaram atividade de ruminação durante o período de observação. Concluiu-se que, em vacas, o amitraz epidural aumenta a latência de resposta a estímulo nociceptivo, sem induzir efeitos colaterais sistêmicos severos nas doses utilizadas, em comparação à dose de 0,05 mg/kg de xilazina epidural

The amitraz is a formamidine compound widely used in the preventive veterinary medicine as an acaricide in small and large animals. Several reports showed that the effects caused by intravenous or epidural administration of this substance are result of its interaction with a-2 adrenoceptors. In the present study, the clinics, behavioral and antinociceptive effects of epidural injection of amitraz were assessed and compared with the effects caused by xylazine administered by the same route. Amitraz (0,1 or 0,4 mg/kg), xylazine (0,05 mg/kg) and 10% DMSO (5,0 mL) were injected epidurally in 4 cow groups and heart rate (HR), systolic arterial pressure (SAP), respiratory rate (RR), ruminal motility (RM), rectal temperature (RT), head height (HH), anal pressure (AP) and latency to heat-evoked reflexes (LSPR - skin of perineal region; LHWR - hoof withdrawal reflex) were evaluated. The HR decreased in amitraz and xylazine groups, but in this group this effect was more evident until 65 minutes. RM was inhibited by amitraz and xylazine until 240 and 180 minutes, respectively. Only xylazine diminished RR, SAP and HH. The LSPR was prolonged in xylazine group (T5-T240) and amitraz 0,4 group (T25-T120). The LHWR after xylazine treatment increased between 15 and 55 minutes, while in amitraz 0,4 group it was higher than basal values between 25 and 120 minutes. The xylazine raised RT. The values of AP decreased during all experimental period after xylazine injection. The animals that received epidural xylazine had ptialism. All the animals of DMSO and amitraz 0,1 group ruminated during the experiment. We concluded that amitraz (0,1 and 0,4 mg/kg) does not produce severe systemic effects after its epidural use, in cows. Xylazine (0,05 mg/kg) causes mild systemic effects following epidural administration. Amitraz (0,4 mg/kg) induces prolongation of the latency to heat-evoked reflexes, in cows