Topic 1 Flashcards Preview

*Medicines Topic 1 + 2 > Topic 1 > Flashcards

Flashcards in Topic 1 Deck (18):
1

Toxicology

the study of poisons, and their undesirable and harmful effects on the body. This includes drugs and medicines, as well as environmental pollutants, animal venoms, poisonous plants and household and workplace chemicals.

2

The principles of pharmacology also apply to toxicology

what is the fate of poisons in the body, what are their actions and how do they produce their effects, how can the effects be reversed or overcome.

3

What characteristics must a drug possess in addition to producing biological effects that make it useful as a scientific tool or as a medicine

- potency
- specificity
- selectivity

4

Potency

refers to the amount of drug required to produce an effect. The more potent the drug, the lower the amount of the drug will be required for a given effect.

5

Specificity

the range of actions in the body or how many different effects it produces. The more specific a drug is, the narrower is its range of actions and the less likely it is to produce side effects. [how many mechanisms or actions drug produces e.g. more selective drugs act on fewer targets]

6

Selectivity

refers to the range of cellular or molecular targets with which a drug interacts in order to produce its effects. For most drugs the molecular target is a protein that functions as a receptor. [how many molecular targets the drug acts on/drugs ability to bind] [usually more selective drugs have 1 or a few targets]

7

Risk of more potent drugs

run the risk of the person taking them overdosing them more easily

8

Specificity example

Histamine 1 receptors (H1R) are found in the brain and immune system. Blocking brain H1R makes you drowsy, blocking immune H1R reduces allergic reaction.

9

Types of histamines

1st generation antihistamines act on brain and immune system - non-specific, side effect: drowsiness
2nd generation antihistamines are specific for immune system receptors

10

Selectivity example

H1 receptors control allergic response, H2 receptors control gastric acid secretion/physiology of gut, Histamine can act at both H1 and H2 receptors (non-selective).

11

What does selectivity depend on

Selectivity depends on the chemical structure and dose of the drug;

12

Why does selectivity depend on the chemical structure of a drug

chemical structure of a drug is a key determinant in how it interacts with the body and alterations in the structure, however minor, can lead to alterations in activity.

13

Why does selectivity depend on the dose of a drug

The dose is important because a drug may have multiple targets but differing potency on different targets. At low doses it may be more selective for one of the targets. This is one of the reasons why a particular drug may be safe at low doses but dangerous at higher doses.

14

Plant sources of drugs

Botanical species taken from trees, shrubs, and other plants formed the mainstay of early medicines

15

Examples of plant sourced drugs

opium, belladonna (nightshade)

16

Examples of animal sourced drugs

bufotoxins (toad poison), honey

17

Why should you isolate active ingredients of natural products

Natural products can be variable in their contents

18

History of plants and drugs

Herb gardens were cultivated for medicinal uses by Native Americans, Aztecs of Mexico and many cultures and was a feature of the medieval monasteries of Europe. Herbal remedies were commonly used to treat illness so it was essential for the physician to have botanical knowledge in order to select and prepare the appropriate treatment. While herbal remedies were valued for their medicinal properties, it was also generally understood that they were potentially poisonous and required careful handling