Sucralfate and fluoroquinolones: Never the twain shall meet?

A delay in drug-switching for treatment of GI issues might be all that's called for. (Photo Getty Images)Gastrointestinal (GI) issues are common in every veterinary practice. Sucralfate is a gastrointestinal protectant primarily indicated for the treatment of gastric erosion in both dogs and people. Most animal hospitals have and use it, but it is known to affect the bioavailability of certain medications in people. Fluoroquinolones are a class of drugs that seem to be affected by simultaneous administration of sucralfate. Up to this point, veterinarians also have been advised to avoid concurrent administration. However, ease of use can affect compliance and success, so if we could give them together, pet owners would be more likely to complete the protocols at home.

A round-robin of trials

To address this issue, a crossover study was performed to determine whether a drug interaction truly exists when sucralfate is given to dogs simultaneously with fluoroquinolones. The study looked at concurrent administration of ciprofloxacin or enrofloxacin with sucralfate and also examined if a two-hour delay between the drug administration was advisable.

Five healthy greyhounds were chosen from a research colony. At varying times in the study, with at least a two-week washout period between protocols, each dog received:

• Only oral ciprofloxacin

• Ciprofloxacin concurrently with sucralfate (1 g sucralfate orally every eight hours starting 24 hours before ciprofloxacin administration, concurrently with ciprofloxacin, and every eight hours after ciprofloxacin administration for two more doses)

• Sucralfate suspension two hours after administration of ciprofloxacin

• Only oral enrofloxacin

• Enrofloxacin concurrently with sucralfate (1 g sucralfate orally every eight hours starting 24 hours before enrofloxacin administration, concurrently with enrofloxacin, and every eight hours after enrofloxacin administration for two more doses)

• Sucralfate suspension two hours after administration of enrofloxacin.

Surprising results

The relative bioavailability of the two fluoroquinolones was evaluated by measuring them in the plasma by liquid chromatography with mass spectrometry. The relative bioavailability for ciprofloxacin was found to be variable when compared with enrofloxacin. Plasma concentrations of ciprofloxacin in the group given sucralfate concurrently indicated a relative bioavailability of ciprofloxacin of 48% when compared with relative bioavailability of ciprofloxacin when ciprofloxacin was given alone. Relative bioavailability of the ciprofloxacin improved to 87% when administration of sucralfate was delayed by two hours. In contrast, relative bioavailability for enrofloxacin even with concurrent sucralfate administration was 104%.

The study suggested a possible clinically relevant drug interaction of ciprofloxacin when given with sucralfate and even suggested that plasma concentrations of ciprofloxacin in dogs were variable regardless. No significant difference in relative bioavailability was suggested for enrofloxacin when given with or without sucralfate.

Exam room application

For practitioners, it seems to be acceptable to give sucralfate simultaneously with enrofloxacin without concern. Looking at the findings of this study, one would need to carefully consider the use of ciprofloxacin in dogs-even without sucralfate. And if use was indicated, a two-hour delay after administration of ciprofloxacin before administration of sucralfate would be advisable. We know that a two-hour delay between medications when treating a pet is inconvenient at best, and these findings can help make lives a little easier for pet owners trying to manage GI issues.

KuKanich K, KuKanich B, Guess S, et al. Effect of sucralfate on the relative bioavailability of enrofloxacin and ciprofloxacin in healthy fed dogs. J Vet Intern Med 2016;30:108-115.

Link to article: http://onlinelibrary.wiley.com/doi/10.1111/jvim.13796/full