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	| Interactions: |  Gentamicin 
Adverse Effect: loss of Gentamicin efficacy     Clinical Management: Monitor patients for Gentamicin effectiveness. 
Methotrexate 
Adverse Effect: an increased risk of methotrexate toxicity     Clinical Management: Avoid the concurrent use of methotrexate and penicillin if possible. If concomitant therapy is unavoidable, consider decreasing the methotrexate dose. 
Neomycin 
Adverse Effect: loss of Neomycin efficacy     Clinical Management: Monitor patients for Neomycin effectiveness. 
Netilmicin 
Adverse Effect: loss of Netilmicin efficacy     Clinical Management: Monitor patients for Netilmicin effectiveness. 
Probenecid 
Adverse Effect: increased penicillin serum levels 
Sisomicin 
Adverse Effect: loss of Sisomicin efficacy     Clinical Management: Monitor patients for Sisomicin effectiveness. 
Streptomycin 
Adverse Effect: Loss of Streptomycin efficacy     Clinical Management: Monitor patients for Streptomycin effectiveness. 
Tetracycline 
Adverse Effect: decreased antibacterial effectiveness     Clinical Management: If possible avoid this drug combination. Monitor decreased antibacterial efficacy. 
Tobramycin 
Adverse Effect: loss of Tobramycin efficacy     Clinical Management: Monitor patients for Tobramycin effectiveness.  |  
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