Psychiatric Drugs Flashcards
Statistics
Psych drugs were the second most popular class of drugs, with antidepressants being most widely prescribed (2017). A top 5 reason for physician visits.
What is a neuron?
nerve cells that transmit info through signals known as action potential. Neurons can send and receive information from other neurons.
How do neurons communicate with each other?
When they reach the end of the axon, the info must be passed along to other neurons.
What is neurotransmission and where does it take place?
Neurotransmission is when neurons send messages (neurotransmitters) to other neurons at the synapse.
What are the four steps of neurotransmission?
Synthesis, Release, Receptor Action, and Inactivation.
Outline Synthesis.
Building blocks of neurotransmitters (like Dopamine and GABA) are imported into the terminal and packed into small vesicles.
Outline Release.
When action potential reaches the terminal, the channels cause influx of calcium to release the transmitter. They are released across the membrane through exocytosis.
Outline Receptor Action
Transmitter passes synaptic cleft and binds to a receptor on the post synaptic membrane.
Outline Inactivation
Transmitter is either taken back to terminal or inactivated. They can be inactivated by enzymes that break down neurotransmitters or through uptake (pack to pre-synaptic neuron).
Which steps do most psychiatric drugs work on?
They impact the 3rd and 4th step of this process.
What is a psychiatric disorder?
Change in mood, behavior or altered thinking. Also associated with significant distress and impaired function over an extended period of time. This impacts productivity and even health care costs.
What are the causes of psychiatric disorders?
40% biological/physiological, and 60% environmental.
Give some examples of causes.
NDPSM
Neurodevelopmental defect (birth trauma or malnutrition can effect brain while its growing).
Drugs- substance abuse is one reason. The use of amphetamines can increase paranoia, hallucinations and trigger onset for psychotic disorder.
Medical conditions - Stroke (oxygen deprivation can impair area of brain that controls emotions and thinking)
Psychosocial experiences - emotional, physical or sexual abuse and neglect
Stress - financial burden, death etc
What are types of disorders?
Mood disorders such as depression, and bipolar disorder.
Psychotic disorders such as schizophrenia.
Anxiety disorders such as panic, excessive worry and fear.
What are psychiatric drugs used for?
- treat psychiatric disorders
- very lipophilic because they can cross blood brain barrier and work in the CNS
- they cannot cure the disorder but provide relief
- usually life long treatment, but some anxiety pills are 6-12 months
- slow onset
- generally have many side effects
- usually have a general overlap
What are the pharmacokinetics of psychiatric drugs?
- often administered orally
- very lipid soluble
- metabolized through liver
- excreted through urine
What are the drug classes for depression?
Antidepressants –> MAOIS, TCAIS, SSRIS, and SNRIS
What are the drug classes for mood disorders like bipolar disorder?
Mood stabilizers–> lithium, and anticonvulsants
What are the drug classes for schizophrenia?
Antipsychotic –> typical and atypical
What are the drug classes for anxiety?
Anxiolytics–> BZDS, and azapirones
What is depression?
Feelings of despair and may be present and may experience multiple episodes over life time.
affects ~8% of population, and 70% prevalent in women
What are the symptoms?
apathy (withdrawal from social life), loss of interest (depressed mood) - one required
weight/appetite changes, sleep disturbances, fatigue, guilt, inability to make decisions or remember things, and suicidal thoughts - 4 required
How long do the depressive symptoms need to persist for?
2 weeks minimum.
What are the MAOIS? (monoamine attached to aromatic ring)
Monoamine Oxidase Inhibitors are drugs that inhibit the Monoamine enzyme from breaking down monoamines such as serotonin, and norepinephrine. The MOA hypothesis states that depression is associated with low levels of S and NE. This leads to increase amount of NE and S available for neurotransmission in synapse for a longer time.
Why should you avoid aged cheese, red wine and poultry while on an MOAIS.
Tyramine is broken down by monoamine oxidase. If monoamine oxidase is inhibited, the tyramine cannot be broken down. Tyramine can displace NE from vesicles and bind to alpha receptors, hence causing vasoconstriction.
What is the first line treatment for depression?
SSRIS. MOAIS are the last line treatment.
What are TCAS? (tricyclic)
Antidepressants that inhibit SERT and NET from taking NE and S back to the pre-synaptic terminal. As a result, it increases amount and time that S and NE remain in synapse.
What are the side effects of TCAS?
- not a very selective drug, has affinity for many receptors
- anticholinergic effects
- orthostatic hypotension (blocks beta receptors)
- sedation
- weight gain
- cardiac arrhythmia
What are SSRIS?
Drugs that selectively inhibit SERT from taking S to pre-synaptic terminal.
What are the side effects of SSRIS?
They have less effects because they are very selective.
- nausea
- headache
- drowsiness
- sexual dysfunction
What are SNRIS?
Drug that selectively inhibits SERT AND NET.
What are the side effects of SNRIS?
Similar to SSRIS. Also, they can increase the chance for hypertension since more NE is available.
What does meta-analysis say about depression?
- anti-depressants are effective in acute depressive episodes, that are moderate to severe.
- Mild depression is better treated with CBT.
What is a bipolar disorder?
Depression and Mania (elated mood)
What are the symptoms?
Need 4 for diagnosis for a week minimum
- hyperactivity–> racing thoughts, fast speaking
- increased irritability, restless
- decreased need for sleep (~4 hrs)
- impulsiveness (reckless behavior)
- grandiose and delusional ideas (superpowers, feeling rich)
What do mood stabilizers do?
effective in treating mania, but needs to be used in conjunction with an antidepressants.
Why should antidepressants not be used alone as a mood stabilizer?
They may induce manic episodes and increase how often it happens.
What is the first line treatment for bipolar disorder?
Lithium
Characteristics of lithium
- slow onset
- can cross BBB with K+ and Na+ transporter since they are readily found in the body
- because it has a charge, it is not metabolized
- has a very narrow therapeutic index. Blood levels should be monitored during treatment
What are the side effects of lithium?
more than 80% experience side effects:
- tremors, hypothyroidism, weight gain, Polyuria and Polydipsia.
- GI symptoms –> vomiting and diarrhea
Why are anticonvulsants used?
If lithium fails
Symptoms of Schizophrenia
deficits in thought processes, delusional thoughts, hallucinations, paranoia, and emotional responsiveness
What is a positive and negative effect?
positive –> adding a symptom
negative –> loosing something as a result
How long do the symptoms need to persist for?
one month minimum, with one positive symptom
What are the positive/negative symptoms?
hallucinations, delusions, disorganized thinking
lack of motivation, social withdrawal, and poverty of speech
Typical anti-psychotics (second line treatment)
- Effective against positive symptoms
- is a D2 receptor antagonist
- effects: involuntary movement, spasms, lip movements, twitching
Schizophrenia is said to be due to_______.
excessive levels of dopamine in the brain
Atypical anti-psychotics (first line treatment)
- D2 antagonists and serotonin receptor antagonists
- treats both pos and neg symptoms
- effects: can cause weight gain, and insulin resistance
The pos symptoms are due to____ and the neg symptoms are due to_____.
a) dopamine
b) seretonin
Symptoms of anxiety disorders
- physiological: intense fear, worry, difficulty concentrating, insomnia etc
- physical: shortness of breath, rapid heartbeat, nausea, trembling, sweating
types of anxiety disorders
panic, generalized anxiety, and phobias (social, agoraphobia)
What is anxiety associated with?
low levels of GABA
What are the drugs of Anxiety?
Benzodiazepines and Azapirones
What do Benzodiazepines do?
-fast onset + long duration
BZDs are selective to benzodiazepine receptors on GABAA receptors, and upon binding enhance the activity of GABA by causing a greater influx of Cl in the neuron, causing hyper polarization and neuronal inhibition (decreases probability of cell firing action potential, and thus decreases brain activity).
Why is the recommended use for BZDS so low?
-drug dependency and tolerance issues
Why should alcohol be avoided when using BZDS?
-can lead to respiratory depression and death
What do Azapirones do?
- slow onset
- good long term treatment
- non sedating
- effects: dizziness, headache, nausea
Why do people not take their meds?
forgetfulness, side effects, paranoia, expense, administration, don’t feel like they have the symptoms
Which of the following is a class of first-line drug class given to patients with anxiety disorders?
SSRIS
