Drugs - Anxiolytics, anti-psychosis

• Give 3 classifications of anxiolytics

  Benzodiazepines, Barbiturates, Anti-depressants
• Give 4 examples of benzodiazepines (Mnemonic: Anxiety & Depression Love Order)


  Diazepam, Alprazolam, Lorazepam, Oxazepam
• Give 2 example drugs of barbiturates (Mnemonic: Pen & Phen)

  Pentobarbital & Phenobarbital
• Benzodiazepine & barbiturates


  Acts on preferentially on midbrain ascending reticular formation & limbic system
• Benzodiazepine & barbiturates


  Mainly work by enhancing activity of gamma-aminobutyric acid (GABA), which is the main inhibitory neurotransmitter in CNS
• Benzodiazepine & barbiturates

  Bind to specific GABA A receptor subunits neuronal synapses
• Benzodiazepine & barbiturates

  Increases affinity of GABA receptors, which enhances inhibitory effects of GABA on CNS
• Mechanism of action of benzodiazepine & barbiturates

  1. Facilitates frequency of GABA-mediated chloride ion channel opening

  2. Enhances membrane hyperpolarization

  3. Decreases neuronal excitability
• Benzodiazepine & barbiturates


  • Causes depressants effects on CNS - sedation & relief of anxiety
• Clinical indications of benzodiazepines and barbiturates

  • acute anxiety states
  • panic disorders
  • generalised anxiety disorders
  • insomnia & sleep disorders
  • for sedation before and during medical & surgical procedures
• Adverse effects of barbiturates & benzodiazepines

  • benzodiazepines are safer anxiolytics than barbiturates
  • CNS depressant effects - drowsiness, confusion, amnesia, impaired coordination such as during driving
  • enhance depressant effect of other drugs such as alcohol
  • tolerance & dependence
• 2 classifications of stimulates

  • naturally-occurring stimulants: Caffeine, nicotine, cocaine
  • synthetic stimulants: amphetamines
• MOA of stimulants

  • cocaine increase extracellular dopamine, serotonin and norepinephrine
  • by binding differentially to their transport proteins
  • hence, preventing re-uptake into these pre-synaptic neurons
• Adverse effects of stimulants

  • anorexia, confusion, exhaustion
  • blood-borne infections with intravenous usage
  • MI
  • in pregnancy, will damage CNS of foetus (Crack baby)
  • withdrawal symptoms: excessive sleep, fatigue, mild depression
• Clinical indications of anti-depressants

  • clinical depression
  • obsessive compulsive disorders (OCD)
  • post-traumatic stress disorder (PTSD)
  • generalised anxiety disorder
  • long-term chronic pain
• 2 classifications of anti-depressants


  selective serotonin reuptake inhibitor (SSRIs) & serotonin-norepinephrine reuptake inhibitors (SNRIs)
• Give 3 drugs of SSRIs. Mnemonic: Feel Calm Soon

  Fluoxetine, Citalopram, Sertraline
• Give 2 drugs of SNRIs. Mnemonic: Dual Victory

  Duloxetine, Venlafaxine
• MOA of SSRIs & SNRIs

  • SSRIs are highly selective, blocking the serotonin transporter, resulting in acute increase serotonergic activity
  • SNRIs & TCAs (Tricyclic anti-depressants) selectively block norepinephrine & serotonin transporter, resulting in acute increase in serotonergic & adrenergic synaptic activity
• Adverse effects of SSRIs & SNRIs

  • SSRIs: Well-tolerated but can cause anti-cholinergic effects (dry mouth, blurred vision, constipation) & sexual dysfunction
  • SNRIs: causes anti-cholinergic effects
  • TCAs: causes weight gain, arrhythmias, seizures when overdose
• Clinical indication of anti-psychotics

  • Schizophrenia & schizoaffective disorders
  • acute mania in bipolar disorders
  • major depressive disorders with psychotic features
  • severe agitation
• Classifications of anti-psychotics with 3 example drugs each

  1st gen (typical): Phenothiazines, Thioxanthene, Butyrophenone

  2nd gen (atypical): Clozapine, Olanzapine, Risperidone
• MOA of anti-psychotics

  • blocks dopamine receptors, specifically D2 receptors in various areas of brain
  • this helps regulate the excessive dopamine activity which contributes to psychotic symptoms: hallucinations, delusions, disorganised thinking
  • some anti-psychotics influences other neurotransmitter systems, including: serotonin, glutamate, norepinephrine
• difference between 1st gen & 2nd gen anti-psychotic drugs

  • 1st gen block D2 dopamine receptors, while 2nd gen blocks D2 dopamine and serotonin receptor antagonist action
  • 1st has more side effects than 2nd gen
  • 1st gen is better to treat +ve symptoms, while 2nd gen can treat +ve & -ve symptoms of schizophrenia
• Adverse effects of anti-psychotic drugs

  • high incidence in extrapyramidal side effects (EPS), especially in 1st gen
  • anti-cholinergic side effects
  • sedation
  • arrhythmias