RESUMO
We studied possible cardiovascular effects (systolic, diastolic, mean arterial blood pressures, and heart rate) caused by intraoral infiltrative administration of 2% mepivacaine HCl with 1:20,000 levonordefrin in dogs (Canis familiaris), using a Beckman electrophysiograph. Doses used were 0.514 and 1.542 mg/kg body weight corresponding to one and three 1.8-ml cartridges, respectively, in 70-kg average weight adult men. A statistically significant increase was observed in the systolic and the mean arterial blood pressures.
Assuntos
Anestésicos Locais/farmacologia , Sistema Cardiovascular/efeitos dos fármacos , Mepivacaína/farmacologia , Nordefrin/farmacologia , Vasoconstritores/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Cães , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Masculino , Sístole/efeitos dos fármacos , Fatores de TempoRESUMO
In rats anestetized with urethane and under ganglionic blockade by hexamethonium (20 mg/kg, i.v.), the i.v. injection of serotonin (60 mug/kg) determined apnea, ECG alterations and a brief hypotensive response which is similar to that as elicited when 5-HT is given to intact rats. During the hypertension which follows that initial response, apnea is still present along with more severe ECG changes. After that, blood pressure falls into a prolonged hypotension, which is invariably accompanied by death. Neither norepinephrine, nor respiratory analeptics (CoramineR, RemeflinF) were able to prevent the fatal outcome. Only artificial respiration was found to be useful in some instances. It was concluded that the association serotonin plus lidocaine becomes lethal when given to ganglion-blocked rate, and this toxic effect can be ascribed mainly to the respiratory depressor activity of the drugs.
Assuntos
Bloqueio Nervoso Autônomo , Pressão Sanguínea/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Lidocaína/toxicidade , Respiração/efeitos dos fármacos , Serotonina/toxicidade , Animais , Apneia/induzido quimicamente , Sinergismo Farmacológico , Eletrocardiografia , Feminino , Compostos de Hexametônio , Hipertensão/induzido quimicamente , Lidocaína/administração & dosagem , Ratos , Serotonina/administração & dosagemRESUMO
It was studied the sensibilizing effect of lidocaine (8.5 mg/kg, i.v.) on the ECG (heart rate, P-R interval, QRS complex and Q-T interval) of both intact and bilaterally vagotomised rats, in the nadir of the final hypotension determined by serotonine (60 mug/kg, i.v.). The results showed (1) a certain degree of selectivity of the vagi, and (2) the effects of serotonine either isolated or associated to lidocaine on P-R interval and heart rate were reinforced when intact animals were used. Although no significant alterations of Q-T were elicited by the drugs, lidocaine surprisingly enlarged the QRS complex in a more significant fashion for the intact than for the vagotomised animals.