Tear production is an important factor in maintaining proper function of the cornea and conjunctiva. The purpose of this study was to determine the effects of bolus followed by infusion of fentanyl, lidocaine, and ketamine on tear production as measured by the Schirmer I Tear Test (STT-I) in dogs. A prospective, randomized, "double-blind" study was performed. A total of 55 healthy conscious client-owned dogs were included in the study. Dogs were randomly allocated to one of four groups and given intravenous fentanyl 0.005 mg kg-1 followed by 0.005 mg kg-1 hour-1 (FEN-group), ketamine 0.6 mg kg-1 followed by 0.6 mg kg-1 hour-1 (KET-group), lidocaine 1 mg kg-1 followed by 1 mg kg-1 hour-1 (LID-group), or saline 0.3 mL kg-1 followed by 2 mL kg-1 hour-1 (SAL-group). The STT-I was performed prior to (baseline) and again 30 minutes (T30) after initiation of drug administration. Data were expressed as the median (minimum - maximum) and analyzed by Wilcoxon and Steel-Dwass tests (P < .05). The STT-I values increased little but were statistically significant in the KET-group from 18 (14-23) to 19 (14-25) (P = .039) and in the LID-group from 21 (14-25) to 20 (17-29) (P = .027). At 30 minutes, STT-I values were significantly higher in LID-group 20 (17-29) than in FEN-group 18 (12-22) (P = .006). Fentanyl, ketamine, and lidocaine administered at the studied doses as a bolus and then followed by an infusion within 30 minutes in healthy conscious dogs demonstrated a clinically insignificant effect on tear production as measured by STT-I.

• Klíčová slova
• fentanyl, ketamine, lidocaine, tear production,
• MeSH
• fentanyl farmakologie   MeSH
• ketamin * farmakologie   MeSH
• lidokain farmakologie   MeSH
• prospektivní studie MeSH
• psi MeSH
• slzy MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie veterinární MeSH
• Názvy látek
• fentanyl MeSH
• ketamin * MeSH
• lidokain MeSH

OBJECTIVE: The aim of this systematic review is to summarize outcomes of studies focused on the effects of opioids, injectable sedative and anaesthetic drugs and inhalant anaesthetics on tear production in dogs. This manuscript complements the systematic review describing the effect of anaesthetics on intraocular pressure in dogs (Pierce-Tomlin et al. 2020). Databases used A detailed search of scientific references has been performed. PubMed, Web of Science, Science Direct and Google Scholar databases were used to search for sources using free text terms 'Dog' or 'Canine', 'Anaesthesia' or 'Anaesthetic' or 'Sedative' or 'Opioid' or the name of used opioids, sedative and anaesthetic drugs and 'Tear' or 'Schirmer' or 'Lacrimation'. The time frame searched was from 1960 to October 2021. Any published manuscripts that were concerned with sedative or anaesthetic drugs administered systemically in the dog and tear production were evaluated. CONCLUSIONS: Low doses of α2-adrenoceptor agonists, neuroleptics, benzodiazepines, opioids, propofol or alfaxalone administered alone have no clinically significant effect on aqueous tear production in healthy dogs measured by the Schirmer tear test I (STT-I). Intramuscular injection of ketamine increases STT-I values. Higher doses of α2-adrenoceptor agonists and combinations of anaesthetics, including inhaled anaesthetics, always clinically significantly decrease tear production.

• Klíčová slova
• Schirmer tear test, anaesthesia, dog, tear production,
• MeSH
• adrenergní receptory MeSH
• anestetika * farmakologie   MeSH
• hypnotika a sedativa farmakologie   MeSH
• propofol * farmakologie   MeSH
• psi MeSH
• slzy MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• systematický přehled MeSH
• Názvy látek
• adrenergní receptory MeSH
• anestetika * MeSH
• hypnotika a sedativa MeSH
• propofol * MeSH

Intraocular pressure (IOP), pupil size (PS), and tear production are variables important in maintaining eye homeostasis. The purpose of this study was to determine the effects of methadone on IOP, PS, and tear production measured by Schirmer I tear test (STT-I) in healthy nonpainful dogs. A prospective, randomized, "double-blind" clinical study was performed. A total of 40 healthy conscious client-owned dogs were included in the study. Dogs were allocated randomly to 1 of 3 groups and given intravenous methadone 0.3 mg/kg (Met-IV, n = 15), intramuscular methadone 0.3 mg/kg (Met-IM, n = 15), or saline 0.3 mL/kg (SAL, n = 10). IOP, PS, STT-I, heart rate (HR), and mean arterial pressure (MAP) were measured prior to (baseline) and at 2, 5, 10, 20, and 30 minutes after drug administration. Data were analyzed using 1-way and 2-way repeated measures ANOVA or their nonparametric equivalents (P < .05). No significant differences in IOP and PS within or between the groups were detected. In the Met-IV group, the STT-I decreased significantly after 30 minutes (P = .025), however, the values remained within the physiological ranges. In Met-IV group, HR decreased significantly at 5, 10, 20, and 30 minutes, respectively. No other significant differences were observed. Methadone administered at a dose of 0.3 mg/kg intravenously or intramuscularly seems to cause within 30 minutes no clinically important effect on IOP, PS, and STT-I in healthy conscious nonpainful dogs without ocular abnormalities.

• Klíčová slova
• Schirmer tear test, analgesic, canine, eye, tonometry,
• MeSH
• methadon farmakologie   MeSH
• nemoci psů * MeSH
• nitrooční tlak MeSH
• oční nemoci * veterinární   MeSH
• prospektivní studie MeSH
• psi MeSH
• pupila MeSH
• tonometrie oční MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie veterinární MeSH
• Názvy látek
• methadon MeSH

Fifty-five healthy conscious dogs were included in a prospective randomised double-blinded clinical study. The dogs allocated to one of four groups received intravenous bolus followed by infusion of fentanyl (FEN-group), or ketamine (KET-group), or lidocaine (LID-group), or saline (SAL-group). The intraocular pressure (IOP), pupil size (PS), heart rate (HR) and mean arterial pressure (MAP) were measured prior to and at 2, 5, 10, 20 and 30 min after initiation of the drug administration. The data were analysed using an analysis of variance and the Steel-Dwass test. No significant difference in the IOP within or between the groups was detected. In the FEN-group, the PS decreased significantly at all the measured times. In the KET-group, the PS increased significantly at 2, 5 and 10 minutes. The PS was significantly smaller in the FEN-group compared to the KET-group at 2, 5, 10 and 20 min, compared to the SAL-group at 5, 10, 20 and 30 minutes. In the FEN-group the HR significantly decreased compared to the baseline and was significantly lower compared to the KET-group and LID-group. Fentanyl, ketamine or lidocaine administered at the doses studied as a bolus followed by a 30-min infusion seem to cause no effect on the IOP in healthy conscious non-painful dogs without ocular abnormalities. Fentanyl decreased and ketamine transiently increased the PS.

• Klíčová slova
• analgesics, canine, eye, pain, tonometry,
• Publikační typ
• časopisecké články MeSH