Chloroquine + Ampicillin = Precautionary

Effect on Concentration

Chloroquine
No change
Applies within class?
No
Ampicillin
Decrease
Applies within class?
No

Pharmacologic Effects

Chloroquine
Effect
N/A
Applies within class?
No
Ampicillin
Effect
N/A
Applies within class?
No

Interaction History

N/A

Last Updated 15-May-2020

Summary

The manufacturer states that Chloroquine significantly reduced the bioavailability of Ampicillin when they are co administered. An interval of at least 2 hours should be observed between chloroquine and ampicillin.

Sources

Reduced ampicillin bioavailability following oral coadministration with chloroquine ^

Study Design

Ampicillin bioavailability was examined in seven healthy adult male volunteers after oral coadministration with chloroquine using the urinary excretion method. Ampicillin (500 mg, capsules) and chloroquine phosphate (250 mg, tablets) were administered in single doses of 1.0 g each. Each subject received, on two different occasions, ampicillin alone and ampicillin together chloroquine. Urine was collected hourly for 8.0 h.

Study Results

The study result indicated a significant reduction in ampicillin bioavailability following the oral co administration with chloroquine. The reduction of ampicillin bioavailability produced by chloroquine might be attributed to slowing of gastric emptying and enhancement of gut motility induced by the chloroquine.

Study Conclusions

Chloroquine increases the gut motility and slows gastric emptying, both of which contributes to reduced bioavailability of ampicillin.

References

Ali, HM. Reduced ampicillin bioavailability following oral coadministration with chloroquine. J Antimicrob Chemother. 1985; 6: 781-4..