Introduction to Pharmacology

Introduction to Pharmacology

• Pharmacology is the study of drugs and their interactions with living systems, encompassing effects, mechanisms of action, and ADME (absorption, distribution, metabolism, and excretion).
• Drug actions can be beneficial or harmful, contingent on the specific drug and its use.
• Pharmacology is linked to chemistry, biology, physiology, and toxicology.

Drug Targets

• Drugs interact with specific molecular targets (receptors, enzymes, ion channels, and transport proteins) within the body.
• Drug-target interactions involve binding and structural changes.
• Identifying the target aids in predicting and controlling treatment responses.
• Selective drugs target specific receptors or enzymes, reducing unwanted side effects.

Drug-Receptor Interactions

• Many drugs bind to specific cell receptors, initiating intracellular processes leading to biological responses.
• Drug potency depends on the strength of the drug-receptor interaction.
• Drug efficacy describes the drug's ability to produce a biological response.
• Affinity is the drug's tendency to bind to a receptor.

Pharmacokinetics

• Pharmacokinetics describes how the body handles drugs, from absorption to elimination.
• Absorption takes the drug from its administration site into the bloodstream.
• Distribution describes drug movement through the body to reach its target.
• Metabolism breaks down drugs into less active or inactive metabolites.
• Excretion removes drugs and metabolites from the body.

Pharmacodynamics

• Pharmacodynamics describes drug effects and mechanisms of action on the body.
• Drug potency measures the drug amount needed for a specific response.
• Drug efficacy signifies the maximum response a drug can elicit.
• Agonists mimic natural ligands, enhancing receptor responses.
• Antagonists block natural ligands' actions on receptors.

Drug Administration

• Drugs can be administered orally, intravenously, intramuscularly, subcutaneously, topically, or inhalational, impacting absorption and bioavailability.
• Oral administration is convenient, but absorption is less predictable.
• Intravenous administration delivers drugs rapidly and completely.

Adverse Drug Reactions

• Adverse drug reactions (ADRs) are unintended negative effects of drug therapy.
• ADRs range from mild to life-threatening.
• Factors including the drug itself, patient characteristics, and concurrent medications influence ADR development.
• Monitoring patients is essential for ADR identification, prevention, and management.

Drug Development

• Drug development is a multi-stage, complex process involving preclinical testing, clinical trials (phases 1-3), and regulatory approval.
• Preclinical testing assesses drug safety and efficacy in animal models.

Drug Design

• Modern pharmacology uses sophisticated drug design to create more selective, potent, and effective medications.
• Computer modeling and high-throughput screening are crucial tools in drug discovery.
• Rational drug design leverages knowledge of the biological target and drug-target interactions.

Drug Interactions

• Drug interactions occur when one drug modifies another's action.
• Interactions manifest as additive, synergistic, or antagonistic effects.
• Prescribers must consider potential interactions with food, other drugs, and patient conditions.

Therapeutic Drug Monitoring

• Therapeutic drug monitoring (TDM) measures drug concentrations in the blood to adjust doses and optimize outcomes.
• TDM ensures drugs remain within their effective and safe concentration ranges.