Week 2 Flashcards
What is pharmacodynamics?
It is the study of the effects of drugs on the body
What does pharmacodynamics involve?
The relationship between the concentration of drug at the site of action and the effect and the relationship between plasma concentration and the intensity of its effects
What is efficacy?
Its the term used to describe the maximum response produced by the drug
What is potency?
It refers to the concentration or dose that is required to produce 50% of the drug’s maximum effect
What is EC50?
Concentration
What is ED50?
Dose
What is an agonist drug?
A drug that activates a receptor to produce a response
What is an antagonist drug?
An antagonist has an affinity but not efficacy and can prevent the agonist from activating receptors
Why do people have different responses to drugs?
Differences in the number/function of receptors, changes in the effector mechanism coupled to the receptor, variations in the concentration of the drug that reaches the receptor or variations in the concentration of substances that compete for the receptor
What is pharmacokinetics?
The study of what the body does to the drug
What are the 4 pharmacokinetic processes?
Absorption, distribution, metabolism and excretion
What is Absorption?
The transfer of the drug from its site of administration into the systemic circulation
What is Distribution?
The reversible transfer of drugs into tissues
What is Metabolism?
Processes of drug elimination: within the liver
What is Excretion?
Processes of drug elimination: Within the kidney
What is a steady state in drug therapy?
It is when doses are given at regular intervals, and the plasma concentration is level. The rate of the drug in equals the rate of drug out.
How is a maintenance dose of a drug worked out?
Using clearance
What does clearance determine?
The rate at which the concentration of the drug is at a steady state
What is bioavailability?
It’s the proportion of a drug or other substance which enters the circulation when introduced into the body and so is able to have an active effect.
What is bioequivalence?
Bioequivalence is the biochemical similarity of two (or more) drugs that share the same active ingredient(s) and desired outcome(s) for patients.
What can alter bioavailability?
Concomitant drugs, food, disease, or missed doses
What are some reasons for lower clearance?
Poor metabolism, other medications, liver or kidney impairment, and elderly
What are some reasons for higher clearance?
fast metabolism, obesity, and pregnancy
Who are at risk of drug interactions?
Anyone who takes 2 or more drugs, people with hepatic or renal disease, people on long-term drugs, people with multiple prescribers, elderly,
Who are at risk of drug interactions?
Anyone who takes 2 or more drugs, people with hepatic or renal disease, people on long-term drugs, people with multiple prescribers, the elderly,
What is a narrow therapeutic index drug?
drugs with small differences between their therapeutic and toxic doses, implying that small changes in dosage or interactions with other drugs could cause adverse effects.
What are the 4 pillars of QUM?
Safety, efficacy, judiciousness and appropriateness
What does teratogenic mean?
Can cause birth defects
What can influence teratogenicity and placental transfer?
Gestational timing of the dose, size of dose and lipophilicity
What does lipophilicity mean?
It is the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene.
What is category A (In pregnancy categories)
Drugs that are taken by a large number of pregnant women without any proven increase of malformations
What is category B1 (In pregnancy categories)
Drugs that are taken by a limited number of pregnant women without any proven increase in malformations
What is category B2 (In pregnancy categories)
Drugs that are taken by a limited number of pregnant women without any proven increase in malformations. The studies in animals are lacking but no evidence in fetal damage
What is category B3 (In pregnancy categories)
Drugs that are taken by a limited number of pregnant women without any proven increase in malformations. Studies in animals have shown evidence of fetal damage.
What is category C (In pregnancy categories)
Drugs that have causes harm to the fetus but not malformations
What is category D (In pregnancy categories)
Drugs have caused or are suspected to have caused damage or malformations
What is category X (In pregnancy categories)
Drugs are not to be used in pregnancy as they cause high levels of permanent drugs
What is some key advice in pregnancy prescribing?
Only use necessary medications, use the lowest effective dose, avoid multiple medications, avoid recreational drugs
What medication can be used when planning a pregnancy?
folic acid
What drugs are often implicated to have drug interactions?
Drugs with a narrow therapeutic index and drugs with a steep dose-response curve
What are 2 drugs which often have drug interactions?
Warfarin and Digoxin
What does pharmacokinetics focus on?
ADME (Absorption, Distribution, Metabolism and Excretion
What does MESS stand for?
Mechanism, Evidence, Severity and Symptoms
What are the best two databses for drug interactions?
MIMS Online & AusDI
What website would be best for information about drugs in pregnancy?
The pregnancy and Breastfeeding guide
