Effects of calcium channel blockers on neuromuscular blockade induced by aminoglycoside antibiotics.
The effects of several calcium channel blockers (nifedipine, verapamil and diltiazem) on rat phrenic-hemidiaphragm preparations were studied. The calcium channel blockers were used either alone or associated with two aminoglycoside antibiotics, neomycin and streptomycin. All drugs investigated produced a concentration-dependent decrease in indirectly elicited diaphragmatic contractions. The order of potency was: verapamil greater than neomycin congruent to nifedipine greater than diltiazem greater than streptomycin. Moreover, neomycin-induced neuromuscular blockade was significantly increased by nifedipine (1 and 10 microM), verapamil (1 and 10 microM) and diltiazem (10 microM), whereas the streptomycin-induced neuromuscular blockade was increased only by nifedipine (1 and 10 microM) and verapamil (10 microM).
D000617:Aminoglycosides / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003964:Diaphragm / Q000187:drug effects; D004110:Diltiazem / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D009355:Neomycin / Q000494:pharmacology; D009466:Neuromuscular Blocking Agents; D009469:Neuromuscular Junction / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013307:Streptomycin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D002121:Calcium Channel Blockers; D009466:Neuromuscular Blocking Agents; D014700:Verapamil; D004110:Diltiazem; D009355:Neomycin; D009543:Nifedipine; D013307:Streptomycin