Adverse Drug Reactions Flashcards
The single largest source of malpractice payouts in the US.
Adverse Drug Reactions
True or False. Despite the efforts to promote patient safety and regardless of the presence of guidelines, the fatalities from drug reaction and interaction have been going up.
TRUE
True or False. Adverse Drug Reactions occur at standard recommended doses.
True.
This characteristic of drugs together with the physiologic and pathologic changes that occur in a person’s body when that person is sick is the cause of ADRs in standard doses.
Drugs are XENOBIOTIC. Meaning, they are inherently toxic.
TRUE or FALSE. Adverse Drug Reactions are noxious and unintended responses to a drug given in wrong doses.
FALSE. ADRs happen when drug is given in RECOMMENDED doses. Otherwise, it’s referred to as an ADVERSE DRUG EVENT or ADE which occurs in any dose.
*OVERDOSE/TOXICITY, which may be intentional or accidental, on the other hand, goes beyond the recommended dose.
TRUE or FALSE. In ADRs, cause is unknown.
FALSE. In ADRs, causality has been determined.
- Adverse Drug Event, on the other hand, occurs at ANY DOSE and CAUSE IS UNKNOWN.
TRUE or FALSE. In drug development, drugs with ADRs may be recycled because a subpopulation could benefit.
TRUE.
ADR + unknown causes + idiosyncratic causes + medication errors + treatment failure =
Adverse Drug Event or ADE
Adverse Drug Events include:
ADRs + Unknown Drug Reactions (Complications & Pre-clinical trials with animals) + Idiosynchratic Causes (Toxicity regardless of dose) + Medication causes (Misunderstanding handwriting & misinformation) + Treatment Failure (counterfeit drugs & quality of generics)
Dose-Related ADRs: Type A (Augmented);
Non-Dose-Related ADRs: ?
Type B (Bizarre)
Dose-Related ADRs (Type A) also:
Covers non-immune ADRs kasi primarily due to pharmacokinetic and pharmacodynamics abnormalities lang (Kaya Type A: AUGMENTED) that produce an excess of known pharmacological drug effect which can be: an Extension Effect or Side Effect
Non-Dose-Related ADRs (Type B) are mainly about Immunological Reactions (yung mga Drug Allergies at mga Hypersensitivity Reactions) and Pharmacogenetic Variations, hence B for Bizarre.
Predictable physiological changes caused by the drug following intended use, but beyond what is normal.
EXTENSION EFFECT in Dose-Related ADRs
- > Ginagawa ng drug yung expected pharmacologic action (pero sobra)
- > Can be managed with dose reduction or shifting to another drug.
Extension Effect of using Aspirin:
GI BLEEDING.
Normal function of aspirin is to inhibit prostaglandins so anti-inflammatory siya -> Kaso lang prostaglandins ALSO PROTECT the mucosal lining of the stomach and the small intestine. -> Ibig sabihin pag nainhibit ang prostaglandins sa stomach at small intestine …-> GI BLEEDING AND EROSIONS!
Predictable physiological changes caused by the drug OTHER THAN intended use.
SIDE EFFECT
- only in Dose-Related ADRs
- Inaatake ng drug yung maling target receptor rather than the one that is intended.
- So difference between Extension Effect and Side Effect in Dose-Related ADRs, Extension = intended use + another effect consequent to intended use (ex. effect of aspirin). Side Effect = other than intended use.
Side effect of Beta-mimetics
PALPITATIONS.
They are cardiotoxic.
Beta-mimetics are the most common tocolytic medications given to women to SUPPRESS preterm labour CONTRACTIONS. The types usually used are called ‘ritodrine’ or ‘salbutamol’ (others can be ‘isoxsuprine’, ‘fenoterol’ and ‘terbutaline’).
Side effect of Aspirin:
PREVENT Thrombus Formation.
since aspirin has anti-platelet action.
From this, we can deduce na Side Effects can be GOOD or BAD and that a drug (such as aspirin) can have both EXTENSION EFFECTS and SIDE EFFECTS.
Variations leading to Dose-Related ADRs?
3P’s
PHARMACEUTICAL VARIATION - Changes in formulation, Outdated formulation, Presence of bacteria & other contaminants.
Example: carbamazepine with added flavors led to patient being stuporous.
PHARMACOKINETIC VARIATION - Variations in LADME (Liberation + ADME) & polymorphisms in Cytochrome P450
PHARMACODYNAMIC VARIATION - Actions of drugs being altered due to intrinsic factors like existence of other diseases other than the one being targeted.
In Pseudocholinesterase deficiency, administration of succinylcholine results to:
Prolonged apnea
Isoniazid Side Effect in Slow Acetylators
Peripheral Neuropathy
Prescribed to prevent peripheral neuropathy in slow acetylators
Vitamin B6 - Pyridoxine
TRUE or FALSE. Pharmacogenetic Variations are under Pharmacokinetic Variations
TRUE.
Liver Toxicity in Fast Acetylators is usually triggered by the use of this drug:
Isoniazid
TRUE or FALSE. Reduced clearance always results in increased adverse reactions.
FALSE. There might be some form of compensatory excretion
Reduced clearance of this drug during hepatocellular dysfunction can lead to ADRs such as hypotension and cardiac failure.
THEOPHYLLINE.
- has narrow therapeutic index
- Theophylline is used for ASTHMA & COPD
Reduced clearance of Phenytoin during hepatocellular dysfunction can lead to ADRs such as:
sedation and coma.
Basta tatlong drugs ang pwedeng itanong regarding their ADRs during hepatocellular dysfunction:
Theophylline na for ASTHMA, ADRs = Hypotension & Cardiac Failure
Phenytoin na ANTI-CONVULSANT, ADRs = sedation & coma
Warfarin na ANTI-COAGULANT, ADRs = more bleeding
