What are the different types of drug-receptor interactions?

Types of drug-receptor interactions encompass these mechanisms:

• Electrostatic interactions: This is the most common mechanism of drug-receptor interactions. It includes hydrogen bonds and Van der Waals forces. 
• Stereospecific interactions: This mechanism is prevalent as more than 50% of drugs exist as stereoisomers and interact with receptors in a sterospecific manner. An example can be seen in S (-) Carvedilol, which binds to α-adrenceptors as well as β-adrenergic receptors, while R(+) Carvedilol binds selectively to α-adrenergic receptors.
• Hydrophobic interactions: Hydrophobic interactions are vital for lipid-soluble drugs and occur between non-polar regions of both the drug and the receptor. 
• Covalent bonds: The least common of all drug-receptor interactions, covalent bonds form when a drug molecules covalently attaches to its receptor. An example is phenoxybenzamine binding to α-adrenergic receptors.