Practical: Drugs in the Eye Flashcards
How are eye infections normally treated?
Allergy+ conditions that cause inflammation: corticosterids (antiinflammatory drugs)
Actue infections: dependant on cause: antibacterials, antifungals, antivirals
In severe cases: systemic treatment
What is constriction and what is dilation of the pupil?
Constriction: Miosis
Dilation:Mydriasis
Which drug types are used to induce mydriasis?
Name an example
Normally antimuscarenic agents are used
e.g. atropine, tropicamide
How would you medically induce miosis?
What is the drug type and name examples
Obtained with muscarenic agonists (e.g. pilocarpine)
What are the effects of tropicamide on
- pupil diameter
- accomodation
Tropicamide is a Muscarenic receptor antagonist
- It dilates the pupil –> relaxation of the constrictor pupillae
- Inpaires near vision (accomondation) –> relaxation of the ciliary muscle) (poit of focus is further away)
What is the clinical use of tropicamide?
Muscarenic receptor antagonist–>
Use in diagnostics of the retina+ lens because of pupil dilation
Explain the effects of pilocarpine on accomodation and pupil diameter
Pilocarpine is a muscarenic receptor agonist causes
- constriction of the ciliary muscle –> very near accomodation
- constriction of the constrictor pupillae –> small pupil diameter
What is the clinical use of pilocarpine?
It increasing aqueous outflow –> used in glaucoma treatment
How does the sympathetic NS influence occular function?
- Dilation pupillae
- aqueous humor production via
- stimmulation of ß2 –> stimmulates production
- also a1 in cillary muscle (vasoconstriction) –> inhibiton of production
- a2 –> inhibiton of production
- Vasoconstrictoon of blood to retina??
How can a sympathomimetic drug be used in the tratment of glaucoma?
If it is alpha selective: reduces blood flow (a1) and inhibits formation of aqueous humor (a2)
How can a ß-blocker be used in the treatment of glaucoma?
Antagonises the ß2-adrenoreceptors in the eye
–> decrease of aqueous humor production
Explain the administration of drugs to the eye in terms of local and systemic effects
It is not easy to get drugs into the eye (local administration) but once they are in, they easily get into body (because of high vasculisation)
Explain the mechanism by which opioids induce miosis
Heroin in stimulating the nerve (CNIII –> normally inhibited by GABA –> heroin is switching off GABA (physiologically done by endorphins)) and therefore causes stimmulation of the PNS –> miosis
Explain the mechanism of action of the prostaglandin analogue Latanoprost in the treatment of glaucoma
Increases drainiage via clearing of the venous drainage channels (no function via the pupil)
Explain the use of Carbonic anhydase inhibitors like Acetazolamide in the treatment of glaucoma
It directly stops ß receptor from producing aqueous humor (by blockign enzyme that produces aqueous humor)
