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Interaction of halothane and antibiotics on isometric contractions on rat-heart muscle
Abstract:
Halothane (H), kanamycin (KM), streptomycin (SM), and chloramphenicol (CM) had direct negative inotropic effects on isometric contractions of isolated rat-heart muscles. Potassium penicillin-G did not show any significant changes in isometric contractions. The depression produced by these antibiotics was characterized by an abrupt onset, rapid progression, and rapid complete recovery, which suggests direct physicochemical rather than metabolic effects. On the other hand, the depression produced by H progressed slowly. When KM, SM, or CM were combined with H, there was a greater depression in isometric contractions than seen in the absence of H, suggesting that the innate characteristics of the antibiotics are augmented when any of them is administered together with halothane.
Insights
Certain antibiotics like kanamycin, streptomycin, and chloramphenicol, along with halothane, negatively impact heart muscle contractions. Combining these drugs intensifies this negative inotropic effect, suggesting synergistic cardiac depression.
Area of Science:
- Pharmacology
- Cardiology
- Toxicology
Background:
- Halothane (H), kanamycin (KM), streptomycin (SM), and chloramphenicol (CM) are commonly used agents.
- Understanding their direct effects on cardiac function is crucial for patient safety.
Purpose of the Study:
- To investigate the direct inotropic effects of H, KM, SM, and CM on isolated rat heart muscle.
- To determine the combined effects of these agents on cardiac contractility.
Main Methods:
- Isolated rat heart muscle preparations were used to measure isometric contractions.
- The effects of individual agents and their combinations were assessed.
Main Results:
- H, KM, SM, and CM demonstrated direct negative inotropic effects, reducing muscle contraction force.
- Potassium penicillin-G did not significantly alter contractility.
- Antibiotic-induced depression was rapid and reversible, suggesting physicochemical mechanisms.
- Halothane-induced depression was slower in onset.
- Combined administration of KM, SM, or CM with H resulted in greater depression than individual agents.
Conclusions:
- KM, SM, and CM exert direct negative inotropic effects on cardiac muscle.
- The cardiac depressant effects of these antibiotics are augmented when co-administered with halothane, indicating potential synergistic toxicity.