From the Guidelines
Levofloxacin has several important drug interactions that can increase the risk of adverse effects, particularly those that prolong the QT interval, such as antiarrhythmics, antipsychotics, and antidepressants, which should be avoided due to the potential for dangerous heart rhythm problems 1.
Drug Interactions
When taking levofloxacin, it is essential to be aware of potential drug interactions that can affect its efficacy or increase the risk of side effects. Some key interactions include:
- Antiarrhythmics: risk of prolonged QT interval
- Antipsychotics: risk of prolonged QT interval
- Antidepressants: risk of prolonged QT interval
- Azole antifungals: increased exposure to certain medications, avoid coadministration for more than 14 days
- CYP3A4 inducers: accelerated metabolism of certain medications, avoid coadministration
- CYP3A4 inhibitors: reduced metabolism resulting in increased serum concentrations of certain medications, avoid prolonged coadministration for more than 14 days
Clinical Considerations
It is crucial to inform healthcare providers about all medications being taken before starting levofloxacin therapy to minimize the risk of adverse interactions. Additionally, patients should be aware of the potential for increased bleeding risk when taking levofloxacin with blood thinners like warfarin, and the risk of hypoglycemia when taking certain antidiabetic medications 1.
Recommendations
Based on the most recent and highest quality evidence, it is recommended to avoid coadministration of levofloxacin with medications that prolong the QT interval, and to exercise caution when coadministering with medications that may increase the risk of bleeding or hypoglycemia 1.
From the FDA Drug Label
The potential for pharmacokinetic drug interactions between levofloxacin and antacids, warfarin, theophylline, cyclosporine, digoxin, probenecid, and cimetidine has been evaluated [see Drug Interactions (7)].
The drug interactions of Levofloxacin (Levaquin) include potential interactions with:
- Antacids
- Warfarin
- Theophylline
- Cyclosporine
- Digoxin
- Probenecid
- Cimetidine 2
From the Research
Drug Interactions of Levofloxacin (Levaquin)
- Levofloxacin has been reported to interact with warfarin, leading to an increase in international normalized ratio (INR) levels 3, 4, 5, 6.
- The proposed mechanism of this interaction is displacement of warfarin from protein binding sites, reduction in gut flora producing vitamin K, and decreased warfarin metabolism 3.
- Studies have shown that concomitant administration of levofloxacin and warfarin can lead to significant elevations in INR values, increasing the risk of bleeding 3, 4, 6.
- Close monitoring of INR values is recommended when levofloxacin is administered jointly with warfarin 3, 4, 5, 6.
- The interaction between levofloxacin and warfarin can be significant, and clinicians should be aware of this potential interaction to guide safe use and monitoring of anticoagulation therapy 3, 4, 6.
- Other antibiotics, such as cefixime, may be a safer alternative to levofloxacin in patients taking warfarin, as they do not appear to increase INR levels to the same extent 6.