Types and mechanisms of adverse effects Flashcards
Side effects caused by histamine H1 blockade
Weight gain
Sedation
Side effects caused by alpha 1 blockade
Orthostatic hypotension
Sedation
Sexual dysfunction including anorgasmia
Priapism
Side effects caused by muscarinic central M1 blockade
Agitation, delirium
Memory impairment
Seizures
Side effects caused by muscarinic peripheral M1 blockade
Dry mouth Ataxia Blurred vision from mydriasis Narrow angle glaucoma Constipation Urinary retention Tachycardia
Antipsychotic side effects which are due to their antidopaminergic effects
Galactorrhoea Gynaecomastia Menstrual disturbance Reduced libido Lowered sperm count Parkinsonism Dystonia Akathisia Tardive dyskinesia
Antipsychotic side effects which are due to their anticholinergic (antimuscarinic) effects
Dry mouth
Blurred vision
Urinary retention
Constipation
Antipsychotic side effects which are due to their antiadrenergic side effects
Postural hypotension
Ejaculatory failure
Antipsychotic side effects which are due to their histaminergic effects
Drowsiness
Tricyclic antidepressant side effects which are due to their antimuscarinic effects
Dry mouth
Urinary retention
Tricyclic antidepressant side effects which are due to their antihistaminergic efffects
Sedation
Weight gain
Tricyclic antidepressant side effects which are due to their antiadrenergic effects
Postural hypotension
Sexual dysfunction
Cognitive impairment
Tricyclic antidepressant side effects which are due to their membrane stabilisation effects
Cardiotoxicity
Reduced seizure threshold
Type of adverse drug reaction which are dose dependent and can be predicted from the pharmacology of the medication
Type A
Type of adverse drug reaction which is idiosyncratic and cannot be predicted from the pharmacology of the medication - includes allergic reactions
Type B
Percentage of adverse drug reactions which type A accounts for
80%
Type I allergic reactions
IgE mediated
Type II allergic reactions
Cytotoxic
Type III allergic reactions
Immune complex
Type IV allergic reactions
Cell mediated
Timing of type I allergic reactions
Minutes to hours after exposure
Timing of type II allergic reactions
Variable
Timing of type III allergic reactions
1-3 weeks after exposure
Timing of type IV allergic reactions
2-7 days after exposure
Type of exposure causing type IV allergic reactions
Cutaneous
Quickest type of allergic reaction
Type I
Clinical features of a type I allergic reaction
Anaphylaxis
Urticaria
Bronchospasm
Clinical features of a type II allergic reaction
Blood abnormalities - neutropaenia, thrombocytopaenia
Clinical features of a type III allergic reaction
Rash
Fever
Urticaria
Vasulitis
Clinical features of a type IV allergic reaction
Allergic contact dermatitis
Rash
Proposed mechanisms of antipsychotic related weight gain
5HT2C antagonism
H1 antagonism
D2 antagonism
Increased serum leptin leading to leptin desensitisation
Mechanism of sexual side effects of SSRIs
5HT2A stimulation
Proposed mechanism for anxiety and agitation sometimes seen on commencing SSRIs
Over stimulation of 5HT2 receptors in the limbic system
Type A adverse effects
Augmented reactions - an exaggeration of a drug’s normal pharmacological action when given at a therapeutic dose. Normally dose dependent
Type B adverse effects
Bizarre reactions - novel responses which are not expected from the known mechanism of action of the drug
Type C adverse effects
Continuing reactions - persist for a long time
Type D adverse effects
Delayed reactions - become apparent after some time of use
Type E adverse effects
End of use reactions - associated with withdrawal of a medication
Mechanism of hypotensive side effects of antipsychotics
Alpha 1 receptor antagonism
Mechanism of SSRI induced nausea and diarrhoea
5HT3 receptor activation
Mechanism of antipsychotic induced tardive dyskinesia
Dopamine receptor super sensitivity
Mechanism of antipsychotic induced akathisia and extra-pyramidal side effects in general
Striatum D2 blockade
Receptor involved in serotonin syndrome
5HT2A
