Pharmacotherapeutics The discipline that studies the use of drugs to cure , delay progression , alleviate symptoms/ signs of a disease or facilitate non-pharmacological intervention cure: eradication of an infection delay progression: medication for hypertension and diabetes alleviate symptoms: paracetamol for pain facilitate non-pharmacological intervention: anesthesia during surgery Pharmacokinetics The discipline that studies fate of drugs in the body (what the body does to a drug) e.g. how the body absorbs a drug from the intestine, how it excretes it and what happens to the drug in between.
Pharmacodynamics Study of the actions/effects of a drug (what a drug does to the body) e.g. why drug A causes an increase in insulin secretion, while B causes a decrease Pharmacoepidemiology Study of both the beneficial and adverse effects of a drug on large number of people Drug A is better for Omani population than drug B , while B is better than A for Chinese population Pharmacoeconomics Study of the cost-effectiveness of drug treatment The cost of drug A exceeds its benefit.
[Audio] A central concept of toxicology is that the effects of a toxin are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to bypass animal testing, while maintaining the concept of toxicity endpoints. There are generally four types of toxic entities; chemical, biological, physical and radiation: Chemical toxicants include inorganic substances such as, lead, mercury, hydrofluoric acid, and chlorine gas, and organic compounds such as methyl alcohol, most medications, and poisons from living things. While some weakly radioactive substances, such as uranium, are also chemical toxicants, more strongly radioactive materials like radium are not, their harmful effects ( radiation poisoning) being caused by the ionizing radiation produced by the substance rather than chemical interactions with the substance itself. Disease-causing microorganisms and parasites are toxic in a broad sense, but are generally called pathogens rather than toxicants. The biological toxicity of pathogens can be difficult to measure because the " threshold dose" may be a single organism. Theoretically one virus, bacterium or worm can reproduce to cause a serious infection. However, in a host with an intact immune system the inherent toxicity of the organism is balanced by the host's ability to fight back; the effective toxicity is then a combination of both parts of the relationship. In some cases, e.g. cholera, the disease is chiefly caused by a nonliving substance secreted by the organism, rather than the organism itself. Such nonliving biological toxicants are generally called toxins if produced by a microorganism, plant, or fungus, and venoms if produced by an animal. Physical toxicants are substances that, due to their physical nature, interfere with biological processes. Examples include coal dust, asbestos fibers or finely divided silicon dioxide, all of which can ultimately be fatal if inhaled. Corrosive chemicals possess physical toxicity because they destroy tissues, but they're not directly poisonous unless they interfere directly with biological activity. Water can act as a physical toxicant if taken in extremely high doses because the concentration of vital ions decreases dramatically if there's too much water in the body. Asphyxiant gases can be considered physical toxicants because they act by displacing oxygen in the environment but they are inert, not chemically toxic gases. As already mentioned, radiation can have a toxic effect on organisms.
Toxicity Injury or death produced by any substance to living organism exposure to carbon monoxide Toxicology The study of harmful effects of drugs and other chemicals on humans, animals or plants principles of pharmacology applied to toxicology Toxinology The study of toxins and venoms.
Regulation of drugs use Food and Drug Administration (FDA) is the government agency responsible for regulating food, dietary supplements, drugs, cosmetics, medical devices, biologics and blood products in the United States Drug Patents granting exclusive right, by the government, to sell a drug; typically for about 20 years.
180px-Panadol_suppositories. Brand name (proprietary name, company name, trade name) Panadol Tylenol Adol Generic name (nonproprietary name) paracetamol Chemical name N-acetyl-p-aminophenol A drug might have different brand names but all share one generic name.
Routes of Administration Enteral (GIT) Sublingual Rectal Oral Parenteral (outside GIT) Intravenous Intramuscular Subcutaneous Others e.g. inhalation, topical.
The choice over different routes depends on several factors: Properties of the drug insulin unstable in gastric acid- parenteral route Systemic vs. local effect paracetamol for headache vs. eye drops for glaucoma Desired onset of action emergency situation e.g. shock parenteral adrenaline Patient characteristics and compliance unconscious parenteral routes compliance and convenience-oral routes pediatric --rectal routes.