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Phase 2a - ICS > ADRs > Flashcards

ADRs Flashcards

1
Q

ADR

A

Adverse Drug Reaction (ADR)
A response to a medicinal product, or combination of medicinal products, which is noxious and unintended.

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2
Q

What are the impacts of ADR for the patient?

A

Reduced Quality of life

Poor compliance

Reduced confidence in clinicians and the healthcare system

Unnecessary investigations or treatments

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3
Q

What are the impacts of ADR for the NHS?

A

Increased hospital admissions

Longer hospital stays

GP appointments

Inefficient use of medication

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4
Q

Classification of ADRs

A

A - Augmented

B - Bizarre

C - Chronic/continuing

D - Delayed

E - End of use/withdrawal

F - failure of treatment

G - Genetic

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5
Q

Type A - Augmented

A

Most common type of ADR (80%).

Exaggerated effect of drugs pharmacology at a therapeutic dose

Often not life threatening

Dose dependent and reversible upon withdrawing the drug

Examples:
AKI with ACE inhibitors
Bradycardia with betablockers
Hypoglycaemia with gliclazide, insulin
Respiratory depression with opiates
Bleeding with anticoagulants

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6
Q

Type B - Bizarre

A

Not related to pharmacology of drug.

Not dose related.

Can cause serious illness or mortality.

Symptoms do not always resolve upon stopping drug.

Examples:
Anaphylaxis with penicillins
Tendon rupture with quinolone antibiotics
Steven Johnson Syndrome with IV vancomycin

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7
Q

Type C - Chronic/continuing

A

ADRs that continue after the drug has been stopped.

Examples:
Osteonecrosis of the jaw with bisphosphonates
Heart failure with pioglitazone

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8
Q

Type D - Delayed

A

ADRs that become apparent some time after stopping the drug.

Examples:
Leucopenia with chemotherapy

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9
Q

Tyep E - End of use/withdrawal

A

ADR develops after the drug has been stopped

Examples:
Insomnia after stopping benzodiazepine
Rebound tachycardia after stopping beta-blocker
Nasal congestion after stopping xylometolazine nasal spray

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10
Q

Type F - Failure of treatment

A

Unexpected treatment failure.

Could be due to drug-drug interaction or drug-food interaction.

Poor compliance with administration instructions.

Examples:
Failure of oral contraceptive pill due to St John’s Wort
Failure of DOAC due to enzyme inducer (eg carbamazepine)
Failure of bisphosphonate due to taking with food

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11
Q

Type G - Genetic

A

Drug causes irreversible damage to genome.

Examples:
Phocomelia in children of women taking thalidomide.

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12
Q

DoTS

A

An alternative way to classify ADRs

Dose-relatedness
Timing
Susceptibility

Provides more details.

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13
Q

Dose-relatedness

A

Hypersusceptibility: ADRs at subtherapeutic doses (anaphylaxis with penicillins).

Collateral effects (side effects): ADRs at therapeutic doses (hypokalaemia with loop diuretic).

Toxic effects: ADR at supra therapeutic doses (liver damage with paracetamol).

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14
Q

Time independent ADRs

A

Develop during any time during treatment (often due to clinical changes in the patient).

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15
Q

Time dependent ADRs

A

Rapid - due to rapid administration, red man syndrome with IV vancomycin.

First dose - first dose only, hypotension with first dose of ACEi.

Early - occur during treatment but resolve as treatment progresses, headache with nitrates.

Intermediate - occur after some delay, interstitial nephritis with penicillins.

Late - risk increases with prolonged or repeated exposure, OA with prednisolone.

Delayed - occur some time after exposure or after drug withdrawal, drug related cancers.

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16
Q

DoTS - Susceptibility

A

Certain patient groups/populations may have a specific susceptibility to ADRs from a drug.

Age (anticholinergics in elderly patients)

Gender (metoclopramide in females)

Disease states (eg diclofenac in CVD)

Physiological states (eg phenytoin in pregnancy)

Susceptibility data may not be known

17
Q

How are ADRs identified?

A

Pre-clinical testing (computer models, cells and toxicity testing in animals)

Clinical trial data (pre-marketing evaluation)

Post marketing surveillance

Pharmacovigilance

SPC form of drugs.

18
Q

Toxicity testing

A

Testing in animals before being given to humans.

Long term administration in different species.

Toxic doses given to identify likely ‘targets’ of toxic effects.

Recovery studies aim to identify irreversible ADRs (e.g. carcinogenesis and neurodegeneration).

Acceptable level of toxicity depends on intended indication.

Findings may halt development of drug or provide focus for future trials

19
Q

What are the three stages of clinical trials?

A

1- administration of 1 dose usually to healthy volunteers (sometimes in patients).

2 - administration of drug to selected populations for which the drug will eventually be indicated. Dose finding.

3 - Randomised controlled trials (RCTs). Any ADRs identified have to be included in the SPC.

20
Q

What are the limitations of pre-marketing evaluation?

A

Low patient numbers

Exclusion of specific patient groups (many at high risk of ADRs):
Elderly, frail
Polypharmacy, multimorbid
Severe organ dysfunction
Neonatal and paediatric population

ADRs with incidence over 1% will generally be identified (most likely Type A).

Less common ADRs (including Type B) are less likely to be identified.

21
Q

Post marketing surveillance

A

Full ADR profile is unlikely to be understood once the drug is in widespread clinical use.

ADR frequency (including rare ADRs)
Identify groups who may be especially susceptible:
- Drug dose ranges
- Gender
- Age
- Disease state

After product licence is granted by MHRA medicines are subject to post marketing surveillance (usually at least 5 years).

Additional monitoring to inform risk-benefit profile when used in everyday practice.

Established medicines may be placed back under post marketing surveillance if the manufacturer wants to amend licence (eg use for a new indication).

22
Q

Black triangle medications

A

Medicines subject to post marketing surveillance are indicated by a black triangle:

BNF (under Medicinal Forms section)

SPC

Patient information leaflet (see below)

All ADRs should be reported for Black triangle medicines!

23
Q

What are the steps of pharmacovigilance?

A

Collect reports of ADRs in everyday use for licensed medicines, unlicensed medicines, herbal medicines, biological products and vaccines.

Monitor known ADRs and identifies previously unknown ADRs.

Assess risk/benefits of the medicine and decide on safest course of action.

Provide information and guidance on identified safety issues to healthcare professionals and public.

24
Q

What are the strengths of the yellow card system?

A

Confidential
No fear of litigation
Quick to submit
Accessible to all (HCPs and patients)

25
Q

What are the weaknesses of the yellow card system?

A

Under-reporting (5% of ADRs and 10% of serious are reported)
Relies on HCPs recognising ADR
Data does not indicate incidence

26
Q

What ADRs need to be reported?

A

Serious ADRs:
Caused hospitalisation
Prolonged hospitalisation
Life threatening
Causing disability or death
Causing congenital abnormalities
Deemed medically significant

Any ADRs caused by black triangle medicine.

Unlicensed uses:
Unlicensed medicines
Off label uses
Herbal medicines
Illicit drugs
Reactions at unlicensed doses (toxicity)

27
Q

What are the four pieces information required to report an ADR?

A

Suspected drug(s)
Suspected reaction(s)
Patient details (initials, Hosp/NHS number)
Reporter details

28
Q

What happens when ADR is confirmed?

A

Adding ADR to product information (BNF, SPC)

Restrictions in use made to product licence:
- Dose, caution in certain patient groups, monitoring
- SPC and BNF will be updated with changes

Change in legal classification
GSL to P, P to POM

Increasing monitoring requirements through black triangle

Medicine may be withdrawn from market

29
Q

Pharmacogenomics

A

Genetic variation can increase risk of ADRs

Expression of CYP450 enzymes (altered drug metabolism)
Eg. ultra-fast metabolisers of codeine

Human Leucocyte Antigen (HLA) alleles can increase risk of immune mediated idiosyncratic ADRs

5-7% of patients prescribed abacavir have severe hypersensitivity reactions

NICE requirement for HLA testing has virtually eliminated these reactions

In most cases genomic risk factors will be unknown (for now)

30
Q

When should we suspect an ADR?

A

Symptoms soon after a new drug is started

Symptoms after a dosage increase

Symptoms disappear when the drug is stopped

Symptoms reappear when the drug is restarted (rechallenge)

Patient concerns

31
Q

Prescribing to reduce the risk of ADRs

A

Rationalise
Stop unnecessary medicines
Thorough and complete DHx (avoid interactions/duplication)
Optimise dose (indication, weight, organ dysfunction, interacting drugs)
Pre-empt ADRs and consider prophylaxis (eg PPI with long term steroids)

Patient counselling
How to take (consider patients with cognitive impairment)
Side effects to expect and/or side effects to report

Appropriate monitoring

Clear and timely communication between care providers (TTOs, outpatient clinic letters, IT systems)

Phase 2a - ICS (43 decks)

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