Drug Toxicology - Priyesh Flashcards
What is a toxic effect?
When you get an unwanted effect of the drug when using its NORMAL concentration
*Normal is important because this will disregard overdose.
What is an example of a Type A reaction - Beta Blockers in glaucoma
Bronchoconstriction - beta receptors in the lungs.
(DO not use on px with asthma or obstructive airways disease)
There is two types of Adverse drug reaction… What is type A?
- Exaggeration of the normal pharmacological reaction of the drug. The higher the dosage the more likely this will happen
Why can we predict Type A reactions?
We know how the drug mechanisms
What is a type B reaction?
This is idiopathic aka fuck knows why these happen. They are rare.
Uncommon and unrelated to the known action of these drugs
What Px variables are involved in an adverse side effect?
- Drug allergy history ; if they are allergic to one drug, there is a possibility they will be allergic to another drug
- Age
- Gender
- Renal/hepatic function (kidney / liver)
- GH
What Pharmacological variables are involved with an adverse side effect?
- Dosage
- Therapeutic Index ; min toxic / min effective
- Formulation ; impact on the gut
route of delivery ; does it go through the liver or not? - Duration
- Multiple drug intervention : like Hypertension drugs
What is digoxin?
Originating from foxglove plant and found in the leaves. It is used to treat heart failure and cardiac arrythmias
- 11-25% will have an OAR
Digoxin mode of action?
It works by inhibiting NA/K ATPase which is found in the heart and in cornea
Side effects of Digoxin?
- Death.
2.Slow pulse
3.Cold sweats
4.Fainting
5.Sickness
6.Confused vision (xanthopsia- they see yellow or green tinge to objects)
What are the black triangles on drugs?
This is showing it is a new drug and needs to be monitored when the px has this as intervention
What is the the yellow card scheme 1964?
- The MHRA (Medicines and Healthcare Products Regulatory Agency) and commissions human medicines monitor this closely.
- It is a database of drugs with voluntary reporting’s of side effects of drugs. Px and clinician report
what does the yellow card cover?
- Adverse effects of P,POM and GS drugs
- Medical devices- Cl products
- Suspecting fake medicines
- E-cigs
What is Vigabatrin?
Drug for epilepsy
Why was Vigabatrin problematic?
It took 10 years to realise the VF loss ; 33% had Peripheral VF loss
What is our role as optometrists detecting ADR?
- Most of them are revisable, early we detect the better.
- Be aware of what drugs can cause ADR, from other clinicians
Types of ADR:
- Blepharoconjunctivitis
- Deposits and opacity in cornea and lens
3.Refractive changes in the lens
4.Uveitis, IOP change and cycloplegia - Retinopathy
- CV disturbances
- Reduced VA
- Scotomas - field changes
- Optic nerve , optic neuritis
When do we detect an ADR?
- Make connection via an unexpected clinical sign when taking a drug.
- Number of reports will help determine the risks of AR
What are the guidelines for recording drug reactions?
- In general population we only interested with life threatening reactions
- However, in children we want to record everything
Where to find information on a drug (reminder)?
BNF, Optometry Formulary
What is chloroquine?
It is used for anti-malaria and rheumatoid arthritis
What adverse effect can chloroquine initiate?
Binds to melanin so it will express as the following:
1.Pigmentary retinopathy
2.Maculopathy - Bullseye pattern
3. VF affected - idiopathic
What is hydrochloroquine?
More modern drug of chloroquine, malaria prophylaxis + rheumatoid arthritis
What is the problem with Hydrochloroquine?
You do not get any pigmentary changes ; it does not bind to melanin like Chloroquine
However, using the OCT we can see there is still adverse reactions.
