Overview of Pharmacology

Definition: Study of drugs, their effects on biological systems, and their therapeutic uses.
Branches:
- Pharmacodynamics: How drugs affect the body.
- Pharmacokinetics: How the body affects drugs (absorption, distribution, metabolism, excretion).

By source:
- Natural (plant-based, animal-derived)
- Synthetic (chemically created)
By therapeutic effect:
- Analgesics (pain relief)
- Antipyretics (fever reduction)
- Antibiotics (bacterial infection treatment)
- Antihypertensives (blood pressure regulation)

Receptor Interaction:
- Agonists: Activate receptors
- Antagonists: Block receptor activity
Enzyme Inhibition: Drugs may inhibit enzymes to alter biochemical pathways.
Ion Channel Modulation: Drugs can open or close ion channels affecting cellular excitability.

Absorption: Movement of drug from site of administration to bloodstream.
- Factors: Route of administration, drug formulation, blood flow to site.
Distribution: Dispersion of drugs throughout body tissues.
- Influences: Blood flow, tissue affinity, protein binding.
Metabolism: Biochemical modification of drugs, primarily in the liver.
- Phase I: Modification (oxidation, reduction)
- Phase II: Conjugation (addition of another substance)
Excretion: Removal of drugs from the body, mainly through kidneys.

Routes of administration:
- Oral (PO)
- Intravenous (IV)
- Intramuscular (IM)
- Subcutaneous (SC)
- Inhalation
Factors influencing dosage:
- Patient characteristics (age, weight, organ function)
- Drug formulation (immediate release vs. sustained release)

Common side effects: Nausea, dizziness, drowsiness.
Adverse reactions: Severe, unexpected responses (allergic reactions, organ toxicity).
Drug interactions: Changes in effect when combined with other drugs (synergistic, additive, antagonistic).

Pregnancy and Lactation: Many drugs cross the placenta; some are contraindicated.
Pediatric Considerations: Dosing differs; children metabolize drugs differently.
Geriatric Considerations: Age-related changes impact pharmacokinetics and dynamics.

Phases of drug development:
- Preclinical testing (laboratory and animal studies)
- Clinical trials (Phase I, II, III, IV)
Regulatory bodies: FDA (U.S.), EMA (Europe), oversee drug approval and monitoring.

Pharmacology is an essential field that combines scientific research and clinical practice to ensure effective and safe medication use. Understanding pharmacological principles is crucial for healthcare professionals in optimizing patient care.

Definition encompasses the study of drugs and their interactions with biological systems, focusing on therapeutic applications.
Major branches include pharmacodynamics, which investigates how drugs have effects on the body, and pharmacokinetics, which examines how the body processes drugs through absorption, distribution, metabolism, and excretion.

Source-based classifications:
- Natural drugs are derived from plants or animals.
- Synthetic drugs are chemically manufactured.
Therapeutic classifications include various drug types such as:
- Analgesics for relieving pain.
- Antipyretics for reducing fever.
- Antibiotics targeted at treating bacterial infections.
- Antihypertensives used for regulating blood pressure.

Drugs may interact with receptors, categorized as:
- Agonists that activate receptor sites.
- Antagonists that block receptor activity.
Enzyme inhibition alters biochemical pathways, impacting drug efficacy.
Modulation of ion channels can influence cellular excitability, either by opening or closing these channels.

Various routes of administration include:
- Oral (PO), intravenous (IV), intramuscular (IM), subcutaneous (SC), and inhalation methods.
Dosage is influenced by:
- Patient-specific factors such as age, weight, and organ function.
- Drug formulation differences, especially between immediate and sustained-release technologies.

Common side effects experienced by patients may include nausea, dizziness, and drowsiness.
Adverse reactions are serious and unexpected, including allergic responses and toxicity to organs.
Drug interactions can lead to combined effects that may either synergize, add to, or antagonize therapeutic outcomes.

For pregnant and lactating women, awareness is crucial as many substances cross the placenta, with certain drugs being contraindicated.
Pediatric dosing differs significantly due to unique metabolism in children.
Geriatric patients face age-related changes that affect pharmacokinetics and dynamics, necessitating adjusted doses.

The drug development process consists of multiple phases:
- Preclinical testing involving laboratory and animal models.
- Clinical trials are divided into four phases (I to IV) assessing safety and efficacy in humans.
Regulatory bodies like the FDA in the U.S. and the EMA in Europe are responsible for the approval and monitoring of new drugs.

Pharmacology integrates scientific research with clinical practice, essential for safe and effective medication use, and is critical for healthcare professionals aiming to optimize patient care.