17.12 Pharmacology: Adverse effects of drugs Flashcards
What does pharmacokinetics describe?
What will happen to the drug in the body: reaching/maintaining dose
(disposition, interactions)
What does pharmacodynamics describe?
What will the drug do in the body: identifying right dose range
(targets and selectivity)
What is a non dose dependent adverse drug reaction?
Hypersensitivity reactions
What are three examples of on target side-effects?
Aspirin (analgesic vs. gastric bleeding)
B-blocker (reduce hypertension vs. worsened asthma)
Adrenaline (localise anaesthetic solutions vs. cardiac excitability)
What is an off target action example of a dose dependent side effect (2)?
Anti-depressants (poor selectivity)
Antihistamine (Terfenadine metabolism)
What is Terfenadine? What pathway metabolises it?
H1 R’ Antagonist (for hayfever)
P450, CYP34A
What is Terfenadine converted to?
What happens?
Fexofenadine
unexpected concentration in blood
What can be a problem when taken with Terfenadine? What happens?
Grapefruit juice
Ventricular arrhythmia
What are some drugs that can alter P450?
Inhibit: erythromycin, ketoconazole
Stimulate: dexamethasone
What are some drugs that can be fatal if overdosed on?
Atropine
Paracetamol
What happens if you take too much paracetamol?
Glutathione needs to mop up intermediate (from P450)
Damage of hepatocytes
What is an example of a dose dependent idiosyncratic effect? (2)
Stop breathing from suxamethonium (if an absence of pseudocholinesterase)
Codeine (CYP2D6 slows metabolism to morphine)
What are two hypersensitivity reactions?
Idiosyncratic (not dose dependent)–>anaphylaxis
Immunological basis (low level exposure)- e.g. Abs in food, hapten in shampoo
What are 4 adverse reactions (side effect, overdose effect, idiosyncratic effect, hypersensitivity reactions) with atropine?
Side effect: anti SLUD
Overdose: death/blurred vision, difficulty swallowing
Idiosyncratic: slowed metabolism
Hypersensitivity reactions: Type I allergic response, red eye
