Drugs Flashcards
What are the steps in drug regulation and development?
Research Discovery Preclinical development Phase 1 Phase 2 Phase 3 Approval and launch Phase 4
What happens in research and development?
- Target identification
- Establish MoA of drug
- Lead optimization
What is lead optimization?
The process of finding the most potent, pharmacodynamic, pharmacokinetic and safe version of a compound by modifying its chemical structure slightly
What happens in the preclinical development stage?
ANIMALS
Establish toxicity and other adverse effects in animals, as well as variation in its effects
What happens in phase 1 of drug development?
HEALTHY VOLUNTEERS
Confirm the drugs effects and dose ranging - must not have any adverse effects/interactions
What happens in phase 2 of drug development?
AFFECTED PEOPLE
Look at therapeutic value and adverse effects
What happens in phase 3 of drug development?
AFFECTED PEOPLE INTERNATIONALLY
Look at clinical benefit when compared to placebo
What happens in the approval and launch stage?
Look at quality, safety and efficacy of drug (NOT cost), and approve drug for marketing and licensing.
NICE will assess the drug to see whether it should be available on the NHS
What happens in phase 4 of drug development?
Postmarketing survelliance and regulatory reviews
Which companies can grant drug licenses in the UK and europe?
- Medicine and healthcare products regulatory agency
- European medicines agency
How long is a standard patent?
20 years (although development takes 15 years so leaves only about 5 years for marketing)
How can drugs sales be protected when a patent runs out?
- Continue to promote the product
- Consider prescription to OTC strategies
- Patent the manufacturing process
Who can drug developers advertise their product to?
Healthcare professionals, NOT the public
This is as long as they comply with the ABPI
Which types of drugs have to go through the EMA ‘centralised procedure’ to be licensed, as oppose to only through the MHPA in the UK?
Cancer drugs
HIV drugs
Advanced therapies
Biotechnology
What are the 4 main methods of pharmacoeconomic assessment?
- Cost minimisation
- Cost effectiveness
- Cost utility
- Cost benefit
What is cost minimisation?
Looking purely at price, assuming equal efficacy between drugs?
What is cost effectiveness?
Looking at price and efficacy of drug
What is cost utility?
Looking at price efficacy and QALY impact of the drug?
What is cost benefit?
Looking at net monetary gain of licensing a drug (ie. How much money it will save the economy vs how much it will cost)
What sources of guidance are there for prescribing?
Cochrane - international
NICE, SIGN - national
Local regional guidelines
What is compliance?
The extent to which the patients behaviour matches the prescribers advice
What is adherence?
The extent to which the patients behavior matches the AGREED recommendations from the prescriber
What is concordance?
The relationship between the patient and the prescriber and the degree to which they agree on treatment
How can patient compliance be measured?
Direct - Plasma drug concs, direct observations
Indirect - clinical outcomes, electronic monitors, diaries
What is therapeutic drug monitoring?
Maintaining plasma drug concs within a target range.
There are 3 components:
- Monitoring plasma drug concentration (ie. actual drug conc)
- Monitoring clinical response (eg. frequency of seizures)
- Measuring pharmacodynamic effects (eg. PEFR, BM etc)
What drugs are commonly monitored in this way, and why?
Some antibiotics eg. gentamicin, vancomycin, ciclosporin Anticonvulsants eg. carbamazepine, phenytoin Corticosteroids Digoxin Methotrexate Lithium Theophylline Warfarin
This is either because they have a narrow therapeutic index or are dangerous in overdose
How can poor adherence be improved?
- Identify the reasons for non-adherence and address them.
- Monitor and regularly review
- Minimise drug number and simplify regimens using calendar packs
What is the biggest barrier to shared decision making?
Time constraints
What is a medication error?
A preventable event due to an error in prescribing, dispensing or administration.
How can medication error be prevented?
Appropriate policies Education Clear prescription writing Electronic prescribing Failsafe devices (eg. insulin pumps) Controlled storage or drug dissension Antidote availability
What is an adverse drug reaction?
A response to a drug which is noxious, unintended and occurs at doses used for normal therapy
How are adverse drug reactions classified, and give examples for each?
Augmented - dose related and predictable (e.g. hypo from insulin)
Bizarre - random and unpredictable (e.g. anaphylaxis)
Chronic - occurs after longterm treatment (e.g. cushings from steroids)
Delayed - occurs a long time after admin/withdrawal (eg. thalidomide)
End - immediate when drug is withdrawn (eg. adrenal insufficiency from steroid withdrawal)
How should you respond if you suspect an ADR?
- Assess nature and severity of reaction
- Take history of presenting symptoms
- Take drug history and review allergies or previous ADRs
- Review adverse effect drug profile in BNF
- Consider further investigation
Where can you find information about ADRs?
BNF
Electronic medicines compendium
Interactive drug analysis profiles
District services
How can ADRs be identified?
Drug development (any stage)
Voluntary reporting
Record linkage
When should you report an ADR with the yellow card?
- Serious drug reaction
- Extremes of age
- Any triangle drug (new)
- Medication error
What is the difference between a pharmacodynamic and pharmacokinetic drug interaction?
Pharmacodynamic - Interaction involving the effect of the drug on the body
Pharmacokinetic - Interaction involving the effect of the body on the drug
Give an example of a pharmacodynamic drug interaction that is:
a) synergistic
b) antagonistic
a) rifampicin and isoniazid for TB
alcohol and benzodiazepine at GABA receptor
b) salbutamol and atenolol at B receptor
morphine and naloxone at mu receptor