Pharmacology is a key subject in D. Pharmacy, and understanding concepts of medicines and there actions are clearly important than just memorizing. In this post, Pharmacology Important questions are explained in simple language, which is useful for MSBTE, AKTU, BTEUP, RUHS and other state boards.
1) Oral Route of Drug Administration
The oral route of drug administration refers to the intake of drugs through the mouth, where solid or liquid dosage forms are swallowed with water or milk and absorbed through the gastrointestinal tract.
Advantages: This is the most commonly used route because it is simple, convenient, economical, and safe. Patients can take medicines by themselves, making self-medication possible, and there are no complications related to injections.
Disadvantages: However, the oral route has several limitations. The onset of action is slow, which makes it unsuitable in emergencies. Irritant or unpleasant-tasting drugs cannot be administered easily. This route cannot be used in unconscious or uncooperative patients. Drugs undergo first-pass metabolism in the liver, complete absorption is not possible, and some drugs may be destroyed by digestive juices.
2) Parenteral Route of Drug Administration
The parenteral route involves the administration of drugs by routes other than the alimentary or gastrointestinal tract.
Types: Common types include intravenous, intramuscular, subcutaneous, intradermal, and intrathecal routes.
Advantages: The main advantage of this route is the rapid onset of action, making it useful in emergencies. It is suitable for unconscious patients and for those suffering from nausea or vomiting. First-pass metabolism is avoided, and drugs that are not absorbed through the gastrointestinal tract can be effectively administered.
Disadvantages: On the downside, self-medication is not possible, and this route is less safe compared to oral administration. It is more expensive, requires trained personnel, and improper aseptic technique can lead to infections. Pain, bruising, and discomfort at the injection site are also common.
3) Absorption and Factors Affecting Drug Absorption
Drug absorption is the process by which a drug moves from its site of administration into the systemic circulation.
Absorption occurs through different mechanisms such as passive diffusion, facilitated diffusion, active transport, and endocytosis.
Factors affecting drug absorption: Several factors influence drug absorption. Liquids are absorbed faster than solids, and smaller particle size enhances absorption. A larger surface area, such as that of the intestine compared to the stomach, increases absorption. Higher drug concentration improves absorption, and lipid-soluble drugs are absorbed better than water-soluble drugs. The pH of the environment plays a role, with acidic drugs absorbed better in the stomach and basic drugs in the intestine. Unionized drugs are absorbed more efficiently. Disease conditions like diarrhoea reduce absorption, and the presence or absence of food can either increase or decrease drug absorption.
4) General Mechanism of Drug Action
The mechanism of drug action refers to the process by which a drug produces its pharmacological effect in the body.
Drugs may act by stimulation, where they increase the activity of specialized cells, such as adrenaline stimulating the heart.
Some drugs act by depression, causing a decrease in cellular activity, for example barbiturates depressing the central nervous system.
Certain drugs act by irritation, producing their effects by causing local tissue irritation.
Replacement therapy involves drugs that substitute deficient substances in the body, such as insulin in diabetes and iron in anaemia.
Cytotoxic drugs act by destroying or damaging cells, as seen with anticancer drugs. Some drugs modify the immune system by altering immune responses, with vaccines being a common example.
Q5) Factors Modifying Drug Action
Drug action can be modified by several factors.
Age affects dosage requirements, with reduced doses needed in newborns and elderly patients.
Body weight influences dosing in obese and underweight individuals.
Sex-related hormonal differences can alter drug response.
The route of administration affects the intensity and onset of drug action.
Timing of administration, such as before or after food, can change drug effects.
Diet may increase or decrease drug absorption.
Genetic factors, including enzyme deficiencies, influence individual drug response.
Cumulation occurs when slow drug excretion leads to accumulation in the body.
Tolerance develops when higher doses are required to achieve the same effect.
Diseases of the liver or kidneys significantly alter drug action.
Drug interactions may result in additive effects, synergism where one drug enhances another, or antagonism where one drug reduces or blocks the effect of another.
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