Pharmacology Flashcards
What are the two main areas of pharmacology?
pharmacokinetics: what the body does to the drug. Pharmacodynamics: what the drug does to the body.
What is a drug?
A chemical substance of known structure, other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Doesn’t include food, nutrients or essential dietary ingredients. The drug causes some kind of biological effect when administered to a living organism.
What is a medicine?
A chemical preparation, which usually but not necessarily contains one or more drugs, administered with the intention of producing a therapeutic effect.
What are drug targets?
Drugs are designed to work through specific targets, and they are specific to those targets.
What is drug specificity?
A key feature of drugs is their specificity, drugs are designed to bind only to certain targets. The specificity is due to the shape at the molecular level of both the drug and it’s target. They will fit together and by getting together will alter the overall shape of the target and hence leading to its action.
What are side effects?
No drugs are absolutely specific- in most cases they will have other actions on other targets which may be quite mild and are called side effects.
What is an agonist?
If the drug activates a process it is called an agonist.
What is an antagonist?
If it doesn’t activate a process but occupies the receptor it is called an antagonist.
What is affinity?
How easily and how strongly the drug binds to the receptor is called its affinity.
What are the four phases after taking a drug?
A: Absorption- from the site of administration. It then needs to be moved around the body.
D: distribution- using the bodies normal transport systems (blood, lymph and cfs) moving down diffusion gradients and being transported locally into cells and tissues.
M: metabolism- as with all substances within the human body, drugs are subject to the enzymatic reactions of metabolic processes.
E: excretion- of the drug or its metabolites.
What are the methods of drug excretion?
The main route is from the liver via the bile into the gut and then faeces or filtration by the kidneys into the urine. There are other routes though, such as through the skin, sweat and other secretions , via the lungs and in breast milk.
Where can drugs be administered in the epithelia?
e.g. skin patches. They can act through the cornea, vagina, and nasal mucosa too.
How do inhaled drugs work?
Drugs can be inhaled and act through the respiratory mucosa or be absorbed in the respiratory portion of the lungs.
What is an intrathecal administration?
Injection into the csf (cerebrospinal fluid)
What are the factors that affect drug absorption?
Typically 75% of the drug will be absorbed within one to three hours, but this will be affected by a number of factors:
Gut content which will affect motility and blood flow to the gut.
Some drugs will cause gastric stasis which will slow down absorption. Conversely too rapid gut movement will also reduce absorption as the drug will move through the gut too rapidly.
Particle size can be adjusted in pharmaceutical formulation to achieve the absorption rates required, a capsule may contain both fast and slow absorbing compartments to extend the duration of effect of the drug.
