YELLOW BOOK SMALL SHORT ANSWER QUESTION Flashcards
Standard deviation (SD)
is a statistical measure of the spread of values. SD is square root of variance
Sensitivity
is a measure of a test’s ability to identify true disease
= dividing the number of true positive results / the total no people with the disease (true positives + false negatives)
Specificity
is a measure of a test’s ability to correctly identify those without disease
= dividing the number of true negative results / the total no people with the disease (true negatives + false positives)
Positive predictive value (PPV)
is a measurement of how likely someone with a positive test results actually have the disease
= number of true positives / numbers who actually have the disease
Factors determining drug penetration into the eye (4)
1 Drug properties
2 Mode of administration
3 Natural ocular barrier
4 ocular inflammation
which size of molecule penetrate the eye better (small vs large)?
example of large molecules
Small
lipid soluble/ water soluble drug better penetrate the eye?
Lipid Soluble
Does high protein-bound drugs penetrate the eye well?
NO
Natural ocular barriers (3)
Epithelial barrier of cornea
Aqueous-Vitreous barrier
Blood-retinal and blood-aqueous barrier
Where does most drug metabolism occurs?
Liver
Where does Suxamethonium metabolism occurs?
Plasma
Where does Vitamin-D metabolism occurs?
Kidney
Where does Neurotransmitters metabolism occurs?
Synapses
Phase 1 reaction (3)
Involves chemically alteration of drugs basic structure
1 Oxidation
2 Reduction
3 Hydrolysis
conversion of ethanol to acetaldehyde is which phase reaction?
Phase 1
Oxidation reaction is subdivided into
subdivided by whether they are effected by cytochrome-linked mixed function oxidases eg cytochrome P450
Phase 2 reaction
involve conjugation
( sulphation ,glucuronidation, methylation or acetylation)
Phase 2 reaction (End product)
end product are generally pharmacologically inactive and water-soluble
Which drugs produce toxic metabolites (2)
Paracetamol and lignocaine
Drug metabolism variables (4)
Genetics
Drugs metabolised more slowly at extremes ages
Liver disease
Drug interaction
Chloramphenicol causes what issue in neonates
circulatory collapse and grey baby syndrome
Induce cytochrome P450
phenytoin, carbamazepine and rifampicin
Inhibit cytochrome P450
chloramphenicol, warfarin , isoniazid
Pupil innervation
the radially arranged dilator pupillae is sympathetically innervated
the circumferentially arranged sphincter pupillae muscle received parasympathetic innervation and constricts the pupil
Pupil innervation (dilator) schematic
Hypothalamus - superior cervical ganglion - internal carotid plexus - LONG CILIARY NERVE - ciliary ganglion (no synapse) - dilator pupillae
Pupil innervation (constrict) schematic
Edinger-westphal nucleus midbrain - III nerve - ciliary ganglion (synapse) - SHORT CILIARY NERVE - sphincter pupillae
Dilator pupillae innervated by which nerve
long ciliary nerve
Sphincter pupillae innervated by which nerve
short ciliary nerve
Dilator pupillae transmission
Dilator pupillae (noradrenergic transmission: alpha receptor)
Sphinter pupillae transmission
Sphinter pupillae (cholinergic transmission: muscarinic receptor)
MIotic (contricts pupils)
Symphathetic antagonist
Parasympathetic agonist
Mydriatics (dilates pupils)
Symphathetic agonist
Parasymphathetic antagonist
how pilocarpine works
Parasymphathetic agonist- direct muscarinic stimulation
how Mydfrin (Phenylephrine) works
Symphathetic agonist - direct alpha receptor stimulation
how Topicamide works
Topicamide is a mydriatics
Parasymphathtic antagonist- blocks muscarinic cholinergic receptors
Where is aqueous produced
ciliary epithelium
Beta blockers ( examples, mechanism of action)
Timolol, reduce aqueous secretion by b2-blockade
Alpha 2- agonist ( examples, mechanism of action)
Brimonidine, reduce ciliary epithelium aqeous secretion
Muscarinic agonist ( examples, mechanism of action)
Pilocarpine, act on cilliary spur to increase aqueous outflow by ‘opening up’ the trabecular meshwork
Prostaglandin F2 alpha analougues ( examples, mechanism of action)
Latanoprost, facilitate aqueous drainage via non conventional or uveoscleral route
carbonic anhydrase inhibitor ( examples, mechanism of action)
dorzolamide, acetazolamide
act on ciliary epithelium to reduce active secretion of aqueous
Cycloplegic drugs (defination)
prevent accomodation and focus on near object by paralysing the ciliary muscle
