Sucralfate binds to protein molecules in damaged mucosa of the GI tract and protects ulcers and erosions from acid penetration, bile, and pepsin. Although considered safe, sucralfate's gastroprotectant activity can decrease absorption of a variety of co-administered common medicines, such as levothyroxine, ketoconazole, theophylline, digoxin, and fluoroquinolones (ie, broad-spectrum antibiotics). Because of this decreased absorption, doses of sucralfate and antimicrobials need to be separated by a few hours, which can not only be a considerable inconvenience for pet owners who cannot break away from work to stagger dosing, but also can affect compliance and therapeutic success as well as contribute to antimicrobial resistance (if instructions to separate doses are not followed).
Enrofloxacin, a second-generation fluoroquinolone, was the first to be developed and FDA approved for dogs and cats. Ciprofloxacin, another second-generation agent, is not FDA approved for use in animals, but it is often prescribed off-label. Both oral enrofloxacin and ciprofloxacin are effective against gram-negative bacteria (eg, Escherichia coli, Klebsiella spp, Enterobacter cloacae, Proteus mirabilis), and enrofloxacin is also active against some gram-positive bacteria. The most common adverse effects of fluoroquinolones are GI related and usually self-limiting. Notably, ciprofloxacin is an active metabolite of enrofloxacin in dogs. However, ciprofloxacin - when administered orally - has been shown to have highly variable absorption in dogs - thus, it is not considered a drug of choice in this species.
The need to co-administer sucralfate (oral suspension) and fluoroquinolones is common in dogs. Drug-drug interactions between sucralfate and fluoroquinolones are well documented in human medicine, but there are no reported data on such interactions in dogs. In a study of healthy humans, the bioavailability of ciprofloxacin when combined with sucralfate was reported as 4% versus ciprofloxacin alone; when there was a 2-hour delay and a 6-hour delay between the 2 drugs, the bioavailability increased to 83% and 96%, respectively. Hence, the current veterinary recommendations of delaying oral sucralfate administration for about 2 hours post-fluoroquinolone administration are based on human studies.
This week's Evidence Based Update reports on the findings of a recent study that evaluated dogs for a drug interaction when fluoroquinolones are combined with sucralfate administration. In addition, they examined whether (or not) a 2-hour delay between fluoroquinolone and sucralfate administration affects fluoroquinolone absorption. Discussion includes:
View this Evidence Based Update
(Running time: 15 mins)
