6.2: Psychopharmacology Flashcards
Experimental Psychopharmacology
the study of medication, or substance, changes in mood, thinking, and behaviour.
Clinical Psychopharmacology
the use of psychoactive medication in treating psychopathology.
APA-‘a recognised specifality field within clinical psychology dedicated to the study and therapeutic use of psychotropic medication, in addition to traditional psychological interventions for the treatment of mental health disorders’
psychiatrists
treat patients with psychoactive (=psychotropic) medication
completed 4 years advanced training in psychopharmacology
American Psychological Association (APA)
- guidelines for psychologist involvement in pharmacological issues
- psychologist must objectivelly assess their competence in pharmacoterapy before offering medication.
- have to evaluate their feelings about medication- can impact communication with patient
- are sensitive to factors that can moderate the interpersonal and biological aspects of pharmacology (age, development, health, culture)
- psychologist have level of knowledge concerning pharma that is appropriate to the population their serve.
- aware of potential of adverse effects
- explore issues around adherence and feelings about medication
- develop a relationship with client where they feel confortable
- maintain appropriate relationship with providers of biological interventions
Psychologists view on Medication
‘feelings and attitudes about medication…affecgt communication with patient’
overall psychologists believe:
- psychiatrists use too many medications
- psychiatrists place too much trust on medicines
- medicines are addictive
- natural medicines are safer
- medicine does more harm than good
differences to consider in addressing mental health
interpersonal:
- in the presentation of psychopathology
- in participation in treatment
- in access to treatment
biological differences in response to treatment:
1. pharmaceutical factors
2. pharmacokinetic factors
3. pharmacodynamic factors
biological differences medicine
- Pharmaceutical Phase
the medication is administered. Medican protocol
- different routes of administration
- different dosages
- repeated dosages
biological differences medication response
- pharmacokinetic phase
the body does something to the medication. medication levels
- differences in medication levels
- absorption, distribution, elimination of drugs
metabolism:
- genetic variation, CYP2D6 enzyme.
- PM: poor metaboliser
- EM: extensive metaboliser
- UM: ultrarapid metaboliser
age related variation in elimination - ie. Diazepam half life, adult:20-70 hours, elderly, 10 days.
biological differences medication
3.Pharmacodynamic phase
the medication does something to the body. medication effects
individual differences medication effect.
drug action, drug effect
Drug action vs. Effect
action:
drug binds to receptor on presynaptic neuron
effect:
action caused by drug.
ie. increase uptake of seretonin by postsynaptic neuron
drug action: binding to receptors
duloxetine (SNRI)- anxiety, depression- seretonin/norepinephrine transporter
diazepam - anxiety, muslce spazms, alcohol withdrawl- GABA type A receptor
zolpidem- sedative-hypnotic drug, insomnia- GABA type A receptor
Alcohol/ethanol- GABA type A receptor
GABA Type A Receptors: These receptors are involved in inhibitory neurotransmission in the brain.
Interaction: influence on drug effect
additive: When two substances produce a combined effect that is the sum of their individual effects
ie. Zolpidem (Ambien) and alcohol both depress the central nervous system (CNS) by enhancing GABA type A receptor activity. The result can slow functions like heart rate and brain activity, but the overall effect is a simple addition of both effects.
can be dangerous, as the combined sedation can impair breathing
synergystic: When two substances interact in a way that amplifies their effects beyond their individual impacts.
ie.Benzodiazepines (e.g., diazepam) and alcohol work together to enhance GABA-mediated inhibitory neurotransmission. The resulting effect is much greater than the sum of their individual actions, leading to profound CNS depression.
Tolerance to Drug Effect
ED50 and TD50:
**ED50: **The dose at which 50% of the maximum therapeutic effect is achieved.
**TD50: **The dose at which 50% of the population experiences toxic effects.
Therapeutic Index:
The gap between the ED50 and TD50 indicates the margin of safety. A large gap means the drug is safer; a small gap means there’s a higher risk of toxicity.
Tolerance:
Repeated use of a drug can increase ED50, meaning more of the drug is required to achieve the same effect.
As the ED50 approaches the TD50, the therapeutic index decreases, reducing the margin of safety and increasing the likelihood of adverse effects.
Tolerance and Danger
First Exposure:
Shows a standard response to a normal dose, where the drug effectively induces sleep without approaching lethal levels.
After Tolerance:
Reduced Effectiveness: The same dose has less effect (shorter sleeping time).
Danger of Overdose: Increasing the dose to compensate for tolerance brings the plasma level closer to the lethal threshold, increasing the risk of severe toxicity or death.
Key Concern:
Individuals developing tolerance to sedatives (e.g., anaesthetics, benzodiazepines) may inadvertently push doses to unsafe levels, resulting in serious adverse effects.
psychologist should have knowledge on medicines- what level?
The slides focus on tolerance, safety, and decision-making when prescribing or using medications, particularly how tolerance can lead to increased risks of adverse effects. Below is a breakdown:
Slide 1: Tolerance to Drug Effect
ED50 and TD50:
ED50: The dose at which 50% of the maximum therapeutic effect is achieved.
TD50: The dose at which 50% of the population experiences toxic effects.
Therapeutic Index:
The gap between the ED50 and TD50 indicates the margin of safety. A large gap means the drug is safer; a small gap means there’s a higher risk of toxicity.
Tolerance:
Repeated use of a drug can increase ED50, meaning more of the drug is required to achieve the same effect.
As the ED50 approaches the TD50, the therapeutic index decreases, reducing the margin of safety and increasing the likelihood of adverse effects.
Slide 2: Tolerance and Danger
First Exposure:
Shows a standard response to a normal dose, where the drug effectively induces sleep without approaching lethal levels.
After Tolerance:
Reduced Effectiveness: The same dose has less effect (shorter sleeping time).
Danger of Overdose: Increasing the dose to compensate for tolerance brings the plasma level closer to the lethal threshold, increasing the risk of severe toxicity or death.
Key Concern:
Individuals developing tolerance to sedatives (e.g., anaesthetics, benzodiazepines) may inadvertently push doses to unsafe levels, resulting in serious adverse effects.
Slide 3: Decision-Making in Medication Use
This slide emphasises critical considerations in assessing the risks and benefits of medications:
Availability of Specialised Psychiatric Care:
Some adverse effects may require specialised care (e.g., managing withdrawal or side effects of psychiatric drugs).
Proportion of Patients Taking Medications:
Understanding the prevalence of drug use in a patient population helps predict potential adverse effects.
Patient Age:
Adverse effects vary by age (e.g., older adults may have impaired metabolism, leading to greater toxicity).
Severity of Adverse Effects:
Clinicians must weigh therapeutic benefits against the risks of side effects, particularly in vulnerable populations.
