.............. are produced when a drug binds to more than one type of receptor.

Explanation

**Step-by-Step Solution:**

1. **Understanding Drug-Receptor Interaction**: Drugs interact with specific receptors in the body to exert their effects. Each receptor has a unique shape and structure that allows it to bind to specific chemical messengers (like hormones or neurotransmitters).

2. **Binding to Multiple Receptors**: When a drug binds to more than one type of receptor, it can lead to unintended interactions. This is because each receptor may have different functions and roles in the body.

3. **Effect of Multiple Bindings**: The binding of a drug to multiple receptors can inhibit or alter the natural functions of those receptors. This can disrupt normal biological processes.

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