Potential oral manifestations of drugs
Gingival enlargement, xerostomia
Therapeutic effects
clinically desirable actions of a drug
Adverse effects
Clinically undesirable reactions
Adverse drug reaction categories
- toxic rxn- side effect- idiosyncratic rxn- drug allergy- interference w natural defense mechanisms
Toxic reaction
Extension of the pharmacologic effect resulting from a drug's effect on the target organs
In a toxic reaction the amount of the
Desired effect is excessive
Side effect is a
Dose-related reaction
Side effects are not
Part of the desired therapeutic outcome
When does a side effect happen?
When a drug acts on no target organs to produce undesirable effects
Side effects are (2)
Predictable and dose related
Idiosyncratic reaction is a
Genetically related abnormal drug response (such as rash or anaphylaxis)
Certain populations are more susceptible to
Certain adverse reactions to adverse drugs
Are idiosyncratic reactions predictable?
No
are idiosyncratic reactions dose related?
No
Certain drugs can reduce
The body's ability to fight infection
Aspirin adverse reactions
GI upset or pain
Aspirin toxicity symptoms
Tinnitus and hyperthermia
Aspirin allergy symptoms
Rash and difficulty in breathing
Exaggerated effect on target tissues
An extension of therapeutic effect caused by the overreaction of a sensitive patient or by a dose that is too large for that patient
An exaggerated effect on target tissues may result from? Why?
Liver or kidney disease. Disease interferes with the metabolism of the drug.
The effect on nontarget tissues is caused by the __________________ action of the drug.
nontherapeutic
Effect on nontarget tissues occur often at ______ doses
High
What can reduce the adverse reactions on nontarget tissues?
Drug dose reduction
Effect on fetal development is also called
Teratogenic effect
What does teratogenic effect mean?
producing a malformed fetus
What are some examples of the relationship between drugs and congenital abnormalities?
- German measles and birth defects- thalidomide and phocomelia (short arms and legs)
Safe administration to a pregnant woman
Pen/erythro/Tylenol/lidocaine
Contraindicated drugs during pregnancy
Text/NSAIDS/benzodiazepines/metronidazole
Local effect of injectable drugs
Irritation, pain, tissue necrosis
Local effect of topical agents
Irritation
Local effect of oral drugs
May cause GI upset
Drug interactions can happen when
The effect of one drug is altered by another drug
Drug interactions can result in?
Toxicity or lack of efficacy
Drug hypersensitivity example
Allergic reaction, hives develop after a drug is given
What must happen for hypersensitivity to occur?
An ingested drug may be metabolized to a reactive metabolite (hapten)
A hapten can function as what?
An antigen after combining with proteins in the body; antigen formed stimulates antibody production
Type I allergic reaction is ____ __________________ mediated
IgE antibody
What occurs when drug Ag+Ab histamine is released? (Type I)
Vasodilation, edema, and inflammation
Are bronchioles affected in a type 1 allergic reaction?
Yes, anaphylactic shock
What are some symptoms of type I allergic reaction? (4)
- rhinitis- asthma- urticaria- dermatitis
What are the acute, life-threatening symptoms of type I reaction?
- hypotension- bronchospasm- laryngeal edema- cardiac arrhythmias
Type II allergic reactions involve?
IgG or IgM (cytotoxic/cytolytic)
Type II: __________ complex is fixed to a circulating blood cell, resulting in ________
Ag-Ab; lysis
2 examples of type II allergic reaction
Penicillin-induced hemolytic anemia & methyldopa-induced autoimmune hemolytic anemia
Type III allergic reaction is also called
Arthus reactions
Type III reaction is _____ mediated
IgG
Type III: ________ complex fixes complement and deposits in the __________ ______________
Ag-Ab; vascular endothelium
What are the symptoms of serum sickness? What is it caused by?
- urticaria skin eruptions, arthalgia, arthritis, lymphadenopathy, and fever- caused by penicillins/sulfonamides
Type IV allergic reaction is mediated by?
Sensitized t-lymphocytes and macrophages
Type IV: Cells contact __ and an _______________ reaction is produced
Ag; inflammatory
Type IV reaction caused by topical drugs causes?
Contact dermatitis
What things can cause type IV reactions?
Poison ivy/poison oak, some jewelry
Idiosyncrasy is a reaction that is?
Neither the drug's side effect nor an allergic reaction
What causes idiosyncrasy?
Genetic determination/immunologic mechanism
Long-term corticosteroid use can result in what?
Decreased resistance to infection
Some immunosuppressive drugs can exacerbate a
Poor oral condition
Lethal dose (LD50) is
One measure of the toxicity of a drug; the dose that kills 1/2 of subjects
Median effective dose (ED 50)
Dose required to produce a specified intensity of effect in 1/2 of the animals
Therapeutic index (TI) formula
LD50/ED50
If therapeutic index is small what is more likely? What about if TI is large?
Small = toxicity is more likelyLarge = drug will be safer
Human studies of drugs: phase 1
Determines biologic effects, metabolism, safe dosage range in humans, toxic effects of drugs
Human studies of drugs: phase 2
Test effectiveness
Human studies of drugs: phase 3
Safety and efficacy must be demonstrated; dosage is determined
Human studies of drugs: phase 4
Involves post marketing surveillance