Pharmacology Flashcards
Diazepam, lorazepam, temazepam, chlordiazepoxide, midazolam
Class: benzodiazepines.
MOA: enhance binding of GABA to GABA-A receptors —> chloride influx —> inhibition of synaptic transmission.
Indication: anxiety disorders (short-term), acute behavioural control, rapid tranquillisation, insomnia (short-term), alcohol withdrawal.
Side effects/contraindications: drowsiness, sedation, coma, dependence. Lower dose in elderly. Avoid in patients with significant respiratory impairment, neuromuscular disease and liver failure.
Citalopram, fluoxetine, paroxetine, sertraline, escitalopram
Class: selective serotonin reuptake inhibitors (SSRIs).
MOA: inhibit neuronal uptake of serotonin, increasing its availability for neurotransmission.
Indication: anxiety and depression.
Side effects/contraindications: GI upset, changes in appetite and weight, hypersensitivity reactions, hyponatraemia. Increased suicidal thoughts. Citalopram prolongs QT interval. Increased risk of bleeding. Serotonin syndrome at high doses or in combination with other serotonergic drugs.
Duloxetine, venlafaxine
Class: serotonin and noradrenaline reuptake inhibitors (SNRIs).
MOA: inhibits reuptake of serotonin and noradrenaline from synaptic cleft, increasing their availability for neurotransmission.
Indication: anxiety and depression.
Side effects/contraindications: GI upset, neurological effects, hyponatraemia, serotonin syndrome, increased risk of suicidal thoughts, QT interval prolongation (venlafaxine).
Reboxetine
Class: selective noradrenaline reuptake inhibitor.
MOA: inhibits reuptake of NA, increasing its availability.
Indication: depression.
Mirtazapine
Class: presynaptic alpha2-adrenoceptor blocker
MOA: antagonist of pre-synaptic alpha2-adrenoceptors, increasing NA and serotonin availability for neurotransmission.
Indication: depression.
Side effects/contraindications: sedation, increased appetite, GI upset, neurological effects.
Amitriptyline, imipramine, lofepramine
Class: tricyclic antidepressants (TCAs).
MOA: inhibit neuronal reuptake of serotonin and NA from synaptic cleft, increasing their availability for neurotransmission. Inhibits muscarinic, H1, alpha1, alpha 2 and D2 receptors (side effects).
Indication: depression, chronic/neuropathic pain.
Side effects/contraindications: dry mouth, constipation, urinary retention, blurred vision, sedation, hypotension, arrhythmias, ECG changes, convulsions, hallucinations, mania, breast changes and sexual dysfunction. Dangerous in overdose. Should not be given with MAOIs.
Phenelzine, moclobemide
Class: non-selective MAOIs (phenelzine), reversible inhibitor of MAO-A (moclobemide).
MOA: inhibits monoamine oxidase, causing accumulation of amine neurotransmitters (dopamine, NA, A, histamine and serotonin).
Indication: depression, phobia (hypochondria), social anxiety disorder.
Side effects/contraindications: hypertensive crisis if patient eats tyramine rich foods (mature cheese, salami, pickled herring, marmite).
Methadone, buprenorphine
Class: opioid agonists.
MOA: binds mu opioid receptors.
Indication: opioid withdrawal, substitution for opioid dependence.
Nicotine replacement therapy, bupropion, varenicline
Class: NA and dopamine reuptake inhibitor (bupropion), selective nicotine-receptor partial agonist (varenicline).
Indication: smoking cessation.
Chlordiazepoxide
Class: benzodiazepine.
MOA: enhance the binding of GABA to GABA-A receptor, allowing Cl- influx, depressing synaptic transmission.
Indication: alcohol withdrawal, delirium tremens.
Side effects/contraindications: drowsiness, sedation, coma. Dependence.
Pabrinex, thiamine
Class: vitamin B1.
Indication: treatment and prevention of Wernicke’s encephalopathy and Korsakoff’s psychosis.
Side effects/contraindications: high dose thiamine IV may rarely cause anaphylaxis.
Acamprosate
Class: weak glutamate antagonist and GABA analogue.
MOA: interacts with glutamate and GABA in CNS restoring balance between neuronal excitation and inhibition.
Indication: maintenance of abstinence in alcohol-dependent patients (anti-craving).
Naltrexone
Class: opioid receptor antagonist.
MOA: reduces the reinforcing effects of alcohol.
Indication: prevent relapse in alcohol-dependent patients and opioid-dependent patients.
Disulfiram
Class: inhibitor of acetaldehyde dehydrogenase.
MOA: prevents breakdown of acetaldehyde to acetate.
Indication: treatment of alcohol dependence.
Side effects/contraindications: if taken with alcohol causes unpleasant side effects such as facial flushing, N+V.
Methadone
Class: opioid agonist.
MOA: binds mu-opioid receptors.
Indication: opioid dependence.
Side effects/contraindications: N+V (on initiation), constipation, arrhythmias, respiratory depression (high doses), dizziness, drowsiness.
Naloxone
Class: opioid antagonist.
MOA: binds mu-opioid receptor acting as a competitive antagonist. When an opioid is present, naloxone displaces it from its receptors, reversing the opioid effects.
Indication: opioid overdose/toxicity associated with respiratory and/or neurological depression.
Side effects/contraindications: may be a significant withdrawal reaction in opioid-dependent patients (pain, restlessness, N+V, dilated pupils, and cold, dry skin with piloerection.
Lithium
Class: mood stabiliser.
MOA: inositol depletion theory, leading to reduced excitatory and increased inhibitory neurotransmission.
Indication: bipolar disorder.
Side effects/contraindications: hypothyroidism, hyperparathyroidism, idiopathic intracranial hypertension, leucocytosis, QT prolongation, renal impairment and weight gain. Long-term use associated with thyroid problems and mild cognitive and memory impairment.
Sodium valproate
Class: mood stabilising anticonvulsant.
MOA: weak inhibitor of sodium channels, reducing neuronal excitability. It also increases GABA content in brain.
Indication: bipolar disorder.
Side effects/contraindications: GI upset, tremor, ataxia, behavioural disturbance, thrombocytopenia, increase in liver enzymes, hypersensitivity (hair loss). Avoid in women of child bearing age (foetal abnormalities) and hepatic impairment.
Carbamazepine
Class: mood stabilising anticonvulsant.
MOA: inhibits sodium channels.
Indication: bipolar disorder.
Side effects/contraindications: GI upset, dizziness, ataxia, hypersensitivity.
Lamotrigine
Class: mood stabilising anticonvulsant.
MOA: inhibits voltage-gated sodium channels and inhibits post-synaptic glutamate (AMPA) receptors.
Indication: bipolar disorder.
Side effects/contraindications: headache, drowsiness, irritability, blurred vision, dizziness, GI symptom, skin rash.
Risperidone, olanzapine, clozapine, aripiprazole, quetiapine
Class: second-generation (atypical) antipsychotics.
MOA: block post-synaptic dopamine D2 receptors. Antipsychotic effects come from blockade of mesolimbic/mesocortical pathway. Aripiprazole is a partial D2 agonist.
Indication: psychosis, schizophrenia (clozapine —> treatment resistant schizophrenia), mania, rapid tranquillisation.
Side effects/contraindications: sedation, extrapyramidal side effects (more common in typical antipsychotics), metabolic disturbance (weight gain, diabetes, lipid changes), prolong QT interval (arrhythmias). Risperidone - hyperprolactinaemia, breast symptoms and sexual dysfunction. Clozapine - agranulocytosis, myocarditis.
Haloperidol, chlorpromazine, flupentixol, sulpiride, prochlorperazine
Class: first-generation (conventional/typical) antipsychotics.
MOA: block post-synaptic dopamine D2 receptors.
Indication: psychosis, schizophrenia, mania, rapid tranquillisation.
Side effects/contraindications: sedative (chlorpromazine), extrapyramidal side effects (movement abnormalities arising from blockade of D2 receptors in nigrostriatal pathway), drowsiness, hypotension, QT interval prolongation (arrhythmias), erectile dysfunction, hyperprolactinaemia (menstrual disturbance, galactorrhoea, breast pain). Avoided in dementia, Parkinson’s disease.
Describe the extrapyramidal side effects of antipsychotics
Acute dystonia - involuntary parkinsonian movements or muscle spasms.
Akathisia - restlessness.
Neuroleptic malignant syndrome - rigidity, confusion, autonomic dysfunction, pyrexia.
Tardive dyskinesia - involuntary repetitive movements e.g. lip smacking.
