BIOL205 Lecture 2: What is a drug?

Questions and Answers

What is the definition of pharmacology?

Study of drugs and their actions and effects on living systems.

According to the WHO, what is a drug?

Any substance or product used to modify or explore physiological systems or pathological states.

What is the difference between a drug and medicine?

A drug is a substance, while a medicine is a drug mixed in a formulation for administration.

Which of the following are important characteristics for administering a drug safely? (Select all that apply)

Adverse drug effects Signup and view all the answers

What does potency refer to in drug characteristics?

Amount of chemical required to produce an effect. Signup and view all the answers

What is specificity in the context of drugs?

Relationship between chemical structure of the drug and pharmacological effects. Signup and view all the answers

Ethanol has a higher specificity than Lorazepam.

False Signup and view all the answers

Which of these are sources of drugs? (Select all that apply)

Minerals Signup and view all the answers

What is a bioequivalence study?

A study to demonstrate whether a generic medicine releases the active ingredient at the same rate and extent as the original. Signup and view all the answers

Match the following terms with their descriptions:

Chemical name = Exact chemical structure and composition Generic name = Non-proprietary name of a drug Trade name = Brand name given by the manufacturer Bioequivalence = Release rate of active ingredients compared to the original Signup and view all the answers

What does drug scheduling refer to?

Classifications that categorize medicines based on their therapeutic use, mechanism of action, and safety. Signup and view all the answers

Study Notes

Overview of Pharmacology

Pharmacology is the study of drugs, derived from the Greek word "pharmakon."
It encompasses the actions and effects of drugs on living systems.

Definition of Drugs and Medicines

World Health Organization defines a drug as any substance used to modify or explore physiological systems or pathological states for the recipient's benefit.
A medicine is a drug formulated for safe administration.

Safe Drug Administration

Understanding necessary aspects of medication is crucial for safe administration:
- Pharmacodynamics: how the drug works.
- Pharmacokinetics: how the body processes the drug.
- Dosage, frequency, and administration route.
- Recognizing pharmacological effects and specific indications.
- Awareness of adverse effects and contraindications.
- Understanding potential drug interactions.

Useful Drug Characteristics

Potency: The amount of a substance required to produce an effect.
Selectivity: The narrow range of actions on specific receptors or tissues.
Specificity: The relationship between a drug's chemical structure and its pharmacological effects.

Alcohol vs. Lorazepam

Alcohol (ethanol) comparison with Lorazepam (benzodiazepine):
- Alcohol has a lower specificity and broader interaction profile than Lorazepam.
- Lorazepam is more potent at lower doses.
- Different mechanisms: Lorazepam facilitates inhibitory neurotransmitter (GABA) action, while alcohol depresses neuronal activity.

Considerations for Drug Characteristics

Factors for evaluating drugs include:
- Ease of administration.
- Absorption efficiency.
- Potency and selectivity.
- Specificity and drug interactions.

Sources of Drugs

Drugs can be sourced from:
- Micro-organisms (e.g., fungi for antibiotics).
- Human and animal products (e.g., adrenaline).
- Minerals (e.g., iron).
- Laboratory synthesised substances (e.g., antidepressants).
- Plants (e.g., caffeine, cocaine, morphine).

Types of Drug Names

Chemical name: Example - 7-chloro-1,2-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one.
Generic name: Non-proprietary name such as diazepam.
Trade name: Brand name like Valium.

Approved Generic Medicines

Examples include:
- Amoxil®
- Ventolin®
- Implanon NTX®
- Lipitor®
- Advil®
- Panadeine Forte®

Generic Prescribing

Generic medicines contain the same active ingredient and can be produced after patent expiration.
They comprise 40% of prescriptions filled by the Pharmaceutical Benefits Scheme (PBS).
The Therapeutic Goods Administration (TGA) demands that generics meet the same quality and manufacturing standards as original brands.

Bioequivalence

Refers to the rate and extent at which the active ingredient of a generic medicine is released into the bloodstream compared to the original.
Bioequivalence is verified through bioavailability studies, with TGA requiring evidence for confirmation.

Drug Classifications

Classifications based on:
- Therapeutic use (e.g., antidepressants).
- Mechanism of action (e.g., monoamine oxidase inhibitors).
- Molecular structure (e.g., tricyclic antidepressants).
- System affected (e.g., CNS depressants).
- Drug schedule classification.
- Pregnancy safety categories (A, B1, B2, B3, C, D, X).

Drug Schedules

Examples of drug classifications:
- Schedule 2: Pharmacy-only medicines, e.g., large packets of paracetamol.

Description

This quiz covers Lecture 2 of BIOL205, focusing on the definition and understanding of drugs. Students will explore the basic principles of pharmacology and the role of drugs in biology. Prepare to engage with key concepts and terms in this essential field of study.