adverse drug reactions dr. rita grace y. alvero. adverse drug reactions introduction
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ADVERSE DRUG REACTIONS
Dr. Rita Grace Y. AlveroDr. Rita Grace Y. Alvero
Adverse Drug Reactions
Introduction
Adverse Drug Reactions
Definition
any response to a drug that is noxious and unintended and that occurs at doses of an appropriately given drug used in man for prophylaxis, diagnosis or therapy
Adverse Drug Reactions
Significance
• adverse - beneficial
• significant - insignificant
• severity
• acute - chronic
• apparent - hidden
Adverse Drug Reactions
Incidence
• 30% - 1 or > ADR
- 3% severe reaction- 0.3% die
• 5% - OP basis
• extremes of age
• ♀ > ♂
• 28% past Hx
Factors Affecting ADR
• Patient Related
• age
• sex
• genetic influences
• concurrent diseases
• compliance with dosing regimen
• total number of medications
• previous ADRs
• misc. (diet, smoking, environment)
Factors Affecting ADR
• Drug Related
• doses, duration
• inherent toxicity
• pharmacokinetics
• pharmacodynamics
Types of ADR
• Type A (Augmented)
• Type B (Bizzare)
• Type C (Continuous)
• Type D (Delayed)
• Type E (Ending of Use)
• Type F (Failure of treatment)
Type A
• 2 types – extension
side effect
Type B
• no formal response curve
• very small doses can elicit the reaction
• immunological
Type C
• continuous, long term
• dose and duration of therapy
Type D
• longer period of time
• carcinogenesis, teratogenecity, immunotoxicity
Type E
• withdrawal reactions
Type F
• substandard
• presence of toxic excipients
• antimicrobial resistance
• tolerance
Recognizing ADRs
• Has this drug ever caused this type of reaction as reported in the lit?
• Is the timing of the patient’s response to the drug typical of previous reports?
• Can other likely reasons or causes for the patient’s syndrome be eliminated?
• Has the patient ever had a similar response to this drug?
• If the drug is discontinued, does the patient improve?
• If the drug is restarted, does the syndrome recur?
Scoring
10 – 12 - likely ADR
7 – 9 - probable ADR
4 – 6 - possible ADR
0 – 3 - unlikely ADR
Management of AD
Points to Remember to Reduce Occurrence of ADR
• Critically review the total cond of the patient
• Use as few drugs as possible
• Know well the drugs that you use
• Do not change from 1 drug to another
• Do not hesitate to use textbooks and other references
• Be very careful when prescribing drugs known to exhibit a large variety of reactions / interactions
Points to Remember to Reduce Occurrence of ADR
• Be aware of interactions
• Regularly make an inventory of the drugs your patient is receiving
• If your patient shows sign and symptom not clearly explained by the course of illness, think of ADR
75 year old femaleDx: HPN (BP – 170/105)Tx: Nifedipine 20 mg BID
Follow - up
1 mo later(1st ff-up)
1 mo later(2nd ff-up)
2 wks later(3rd ff-up)
1 mo later(4th ff-up)
BP 120/70 BP controlled BP controlled BP 180/100
Problems- dizziness- dyspepsia- swollen ankles
swollen ankleshypokalemia
gout
TxNifedipine 20 mg BIDFurosemide 2.5 mg ODRanitidine 150 mg BID
NifedipineFurosemide 5 mg ODK supplement 2 tab BID
NifedipineFurosemideK supplementsDiclofenac 50 mg TID + Allopurinol
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