Objective—To determine clinical signs and outcomes of methylphenidate hydrochloride (MPH) toxicosis in dogs; to assess effects of amount (ie, dose) and formulation (immediate or extended release) of ingested MPH on onset, duration, and severity of clinical signs; and to describe management of MPH intoxication.
Design—Retrospective case series.
Animals—128 dogs with MPH toxicosis or exposure.
Procedures—Data from an Animal Poison Control Center (APCC) database from November 1, 2001, to November 30, 2008, were reviewed. Records of dogs were searched for APCC classifications of confirmed (n = 71) or suspected (39) MPH toxicosis; dogs (18) that ingested MPH but did not develop clinical signs of toxicosis were also included. Signalment, dose, clinical signs, treatment, and outcome were evaluated.
Results—Clinical signs of toxicosis were reported in 107 of 128 (84%) dogs that ingested MPH; these included hyperactivity in 42 (33%), tachycardia in 27 (21%), vomiting in 19 (15%), agitation in 16 (13%), and hyperthermia in 13 (10%). Doses ranged from 0.36 mg/kg (0.164 mg/lb) to 117.0 mg/kg (53.18 mg/lb). Severity of clinical signs was not strongly associated with dose. More severe and prolonged clinical signs were associated with ingestion of extended-release formulations of MPH; 3 dogs that consumed these formulations (doses, 10.2 mg/kg [4.64 mg/lb], 15.4 mg/kg [700 mg/lb], and 31.1 mg/kg [14.14 mg/lb]) died. Favorable outcomes were reported for most (31/34 [91%]) dogs.
Conclusions and Clinical Relevance—Ingestion of even small amounts of MPH can cause severe clinical signs in dogs. Monitoring and supportive care are recommended regardless of dose.
Objective—To compare procedure times and major and minor complication rates associated with single-chamber versus dual-chamber pacemaker implantation and with 1-lead, 2-lead, and 3-lead pacemaker implantation in dogs with clinical signs of bradyarrhythmia.
Design—Retrospective case series.
Animals—54 dogs that underwent pacemaker implantation because of clinical signs of bradyarrhythmia.
Procedures—Medical records of dogs that received pacemakers between July 2004 and December 2009 were reviewed for information regarding signalment, diagnosis, pacemaker implantation, pacemaker type, complications, and survival time. Analyses were performed to determine significant differences in anesthesia time, procedure time, and outcome for dogs on the basis of pacing mode and number of pacing leads.
Results—28 of 54 (51.9%) dogs received single-chamber pacemakers and 26 (48.1%) received dual-chamber pacemakers. Mean ± SD procedural time was significantly longer for patients with dual-chamber pacemakers (133.5 ± 51.3 minutes) than for patients with single-chamber pacemakers (94.9 ± 37.0 minutes), and procedure time increased significantly as the number of leads increased (1 lead, 102.3 ± 51.1 minutes; 2 leads, 114.9 ± 24.8 minutes; 3 leads, 158.2 ± 8.5 minutes). Rates of major and minor complications were not significantly different between dogs that received single-chamber pacemakers and those that received dual-chamber pacemakers or among dogs grouped on the basis of the number of pacing leads placed.
Conclusions and Clinical Relevance—Although dual-chamber pacemaker implantation did result in increased procedural and anesthesia times, compared with single-chamber pacemaker implantation, this did not result in a higher complication rate.