Pharmacokinetics and toxic effects of lithium chloride after intravenous adminstration in conscious horses.

The research article discusses a study conducted on the effects of intravenous lithium chloride administration in conscious, healthy horses, especially its pharmacokinetics and potential toxicity.

Objective and Methodology

The main aim was to understand the pharmacokinetics – how the drug is absorbed, distributed, metabolized, and excreted in the body – and potential toxic effects of lithium chloride (LiCl) when administered intravenously in healthy horses. This involved:

• Using a sample of six healthy Standardbred horses.
• Administering twenty 3-mmol boluses of LiCl with a concentration of 0.15 mmol/liter at three-minute intervals, totaling 60 mmol over an hour.
• Collecting blood samples pre-injection and up to 24 hours post-injection to measure serum lithium concentrations.
• Evaluating behavioral and systemic toxic effects of LiCl.

Results

The study drew the following conclusions:

• Lithium elimination best fit a tri-compartmental model in five of the six horses.
• The mean peak serum concentration was 0.561 mmol/L, ranging between 0.529 to 0.613 mmol/L.
• The mean serum lithium concentration was 0.575 mmol/L (ranging between 0.52 to 0.67 mmol/L) at 2.5 minutes after administering the last bolus.
• The half-life of lithium was found to be approximately 43.5 hours, ranging between 32 to 84 hours.
• 24 hours after administering the lithium, the mean serum lithium concentration was 0.13±0.05 mmol/L, with a range of 0.07 to 0.21 mmol/L.
• Administering a 60-mmol dose of LiCl did not significantly impact any measured hematological or biochemical variables, gastrointestinal motility, or ECG variables across the study period.

Conclusion

Based on their findings, the researchers concluded that the distribution of lithium best fits a three-compartment model, and its clearance from the body is slow. Importantly, the healthy horses tolerated doses of LiCl that were higher than those required for determining cardiac output, with peak serum concentrations not reaching toxic levels as reported for other species. This suggests that LiCl could potentially be used safely in equine medical treatments, as long as the doses are controlled and monitored.