Final answer:
Penicillins can cause cardiac and renal toxicity through allergic reactions, electrolyte imbalances, and direct toxic effects on the heart and kidneys.
Step-by-step explanation:
Penicillins can cause cardiac and renal toxicity through various means. One mechanism is by inducing an allergic reaction in which the immune system mistakenly identifies penicillin as a threat and triggers an inflammatory response. This immune response can damage the heart and kidneys. Additionally, penicillins can disrupt the balance of electrolytes in the body, leading to electrolyte imbalances that can affect cardiac and renal function. Finally, some penicillins, particularly high-dose and prolonged use, have been associated with direct toxic effects on the heart and kidneys.