Adverse Drug Reactions And Drugs Of Abuse Flashcards
Define adverse drug reactions
Any response to a drug which is noxious, unintended, and occurs at doses used in man for prophylaxis or diagnosis or therapy.
what factors about a person can cause change in the reaction to a drug
What factors can explain reasons ADR
Genetic
Age related
Sex related
Physiological (pregnancy)
Exogenous (drugs)
Disease related
What groups are ADR separated into
Group A and group B ( however it goes all the way to F )
What does a type A ADR stand for
Augmented ADR (dose related)
What does type B ADR stand for
Bizarre (ideosincratic)
What does type C ADR stand for
Chronic
What does type D ADR stand for
Delayed
What does type E ADR stand for
End of treatment
What does type E ADR stand for
End of treatment
What are some features of type A ADRs
Common and related to pharmacological reactions of drugs
Predictable effects
Low mortality
High morbidity
Why might type A reactions occur
1- pharmaceutical variation : changes in bioavailability
-out of date formulations
- contamination
2- pharmacokinetic variation : liver disease
- renal disease
- cardiac disease
3- pharmacodynamic variation : changes in fluid / electrolyte balance
What’s an example of pharmaceutical variation
Outdated tetracycline
- once out of date breaks down into anhydrotetracycline which is toxic and can cause fanconis syndrome
- which causes an impairment in proximal tubule function
- meaning substances that are usually absorbed back into the blood are lost in the urine
What’s an example of pharmacokinetic variation
E.g. liver disease
- severe hepatitis or advanced cirrhosis can reduce clearance of drugs
- means first pass metabolism will be reduced, so more drug gets into the system unchanged, possibly causing a class A ADR
What’s an example of pharmacodynamic variation
E.g. digoxin (used to treat heart disease)
- it works by blocking the Na/k pump of cardiac muscle cells
- when potassium levels are low, more digoxin can bind
- increases its effects - toxic
Hypernatururea
Increase in sodium in the urine
What’s one way to treat a type A ADR
By changing the amount of the drug administered
What are the features of a type B ADR
Uncommon and not related to the pharmacological reactions of drugs.
Unpredictable
High mortality/ low morbidity
How can type B ADRs be managed
By withholding and avoiding the drug in the future
Why might type B reactions occur
Immunological reasons
Pseudo-allergic reactions
What’s an example of a Type B immunological reaction
Allergy e.g to penicillin
- can cause anaphylactic shock
What’s an example of a type B pseudo-allergic reaction
Aspirin sensitive asthmatics
— 3-5% of asthma sufferers suffer attacks that can be triggered by aspirin
What is a pseudo allergic reaction
Reactions that resemble allergic reactions but no immunological basis can be found
What are the types of type C ADRs
Tolerance, adrenal suppression, tardiness dyskinesia
What is the adrenal suppression Type C ADR
-the production of glucocorticoid hormones are controlled by negative feedback ( which are used to treat chronic inflammatory conditions)
- prolonged treatment with high does can cause the body to suppress glucocorticoid by the adrenal cortex
What is tardive dyskinesia
Involuntary jerking movements in the face or the neck
What’s are the features of Type D ADRs
Uncommon
Dose related
Occurs after some time using the drug
How can type D ADRs be managed
They’re often intractable
What are the features of Type E ADRs
Uncommon
Occurs soon after the withdrawal of the drug
How can type E ADRs be managed
Reintroduce and withdraw slowly
What’s an example of a type E ADR
Opiate withdrawal syndrome
What are the features of a class F ADR
Common
Dose related
Often caused by drug interactions
How can class F ADRs be managed
Increased dosage
Consider effects of combinant treatment
What’s an example of a type F ADR
Inadequate dosage of oral contraceptives
Define pharmacogenetics
The study of the influence of hereditary on both the pharmacokinetics of drugs and the pharmacodynamic responses to them
What are some examples of pharmacogenetic variation
What are some classes of drugs of abuse
Opioids - morphine, methadone
CNS Depressants - alcohol, ketamine
Psychomotor stimulants - cocaine, amphetamine
What makes drugs of abuse different than other drugs
They induce feelings of euphoria and reward
- chronic exposure causes continual reliance on its effects
-
Describe Neuro adaptation as a cause of drug tolerance
Receptor expression is dynamic and can change when a drug impacts the system (reduced receptor expression for agonists, increased for antagonists)
This reduces drug effects and leads to withdrawal symptoms
What is the reward pathway
A dopaminergic pathway from the ventral tegmengal area to the nucleus accumbens and prefrontal cortex
What is an example of research behind the reward pathway
Experiment on rats self administering cocaine due to the pleasure it causes them
What are the features of opioids and how do they work
They’re agonists at mu-opioid receptors in the cns to produce main action
- also act on other opioid receptor subtypes
- they also act on peripheral mu-receptors e.g in the gastrointestinal tract
Why do we have opioid receptors int he first place
We have endogenous agonists of these receptors
- endomorphins
- dynorphins
These peptides posses analgesic activity through their precise function in the CNS
and elsewhere poorly understood
They act on opioid receptors of which there are 3 types
Mu, delta, and kappa
