Distinguished future physicians welcome to Stomp on Step 1 the only free video series
that helps you study more efficiently by focusing on the highest yield material.
I’m Brian McDaniel and I will be your guide on this journey through Psychiatric Medications.
This is the 9th video in my playlist covering all of Psychiatry for the USMLE Step 1 medical
board exam.
I already covered antidepressants in the previous video so this video will just cover Antipsychotics,
Mood Stabilizers and Anxiolytics.
We will start with Antipsychotics.
I am giving the overall class a High Yield Rating of 9 on a scale from 1 to 10 based
on a number of factors including how frequently these types of questions have appeared on
retired Step 1 questions.
When you break down the topic further you can see by far the most important material
is the side effects related with these medications.
So make sure you focus your studying on the adverse reactions.
We will start with a quick review of some material from my previous video on psychosis.
Symptoms of schizophrenia can be broken down into 2 categories, Positive and Negative Symptoms.
Positive symptoms include behaviors or sensations that are not normally present.
Examples include hallucinations, delusions, and catatonia.
These symptoms are thought to be related to an excess of dopamine.
I remember this by remembering that “doPamine has a P in it”.
So P for Positive and P for Dopamine.
Negative symptoms are the absence of normal behavior.
Examples include a lack of initiative, diminished speech, disheveled appearance & flat affect.
These symptoms are thought to be related to an excess of serotonin.
As we will see antipsychotics affect dopamine and serotonin to varying levels.
The indications for this class of drugs includes psychosis (mainly schizophrenia), Mania (mainly
bipolar disorder), aggression and Tourette's disease.
Here is the list of the highest yield antipsychotics.
I’ve included the trade name for some of them just for your reference, but remember
the exam will only include generic names.
The Typical Antipsychotics (AKA 1st Generation Antipsychotics or Neuroleptics) include Haloperidol,
Fluphenazine, Thioridazine & Chlorpromazine.
Most of them end in “Azine.”
Atypical Antipsyhcotics (AKA Second Generation Antipsychotics) include Risperidone, Aripiprazole,
Quetiapine, Olanzapine, and Clozapine.
Most of them end in “Apine.”
Typical Antipsychotics primarily block dopamine receptors in a non-specific manor.
Therefore, these drugs work best for positive symptoms, and have little effect on negative
symptoms.
The non-specific mechanism of the drug also means there are lots of side effects.
Some of these medications come in a slow release injectable form so they can be used in non-compliant
and aggressive patients.
There are a lot of high yield side effects so we will break them down one by one
Neuroleptic Malignant Syndrome (or NMS) is a rare but potentially fatal adverse reaction
of typical antipsychotics.
It involves fever, altered mental status, rigidity and autonomic instability (such as
tachycardia, hypertension, diaphoresis etc.).
You may also see elevated myoglobin in blood or urine and elevated Creatine Kinase (CK).
One of the ways I think about it is that it looks kinda sorta like Serotinin Syndrome
that you can see with antidepressatns.
If you see this you have to emergently stop the medication, provide supportive care and
consider adding Dantrolene (Think DOWN-trolene)
Extrapyramidal Symptoms (or EPS) are due to blockage of Nigrostriatal dopamine.
It can present with a number of different symptoms.
Akasthisia is a general sensation of restlessness Acute Dystonia is involuntary continuous muscle
contractions often of the neck.
Another common presentation of acute dystonia is Oculogyris Crisis when your eyes get locked
looking upward and you have to lean over to see
Dyskinesia (AKA Pseudoparkinsonism) presents like Parkinson’s Disease with symptoms like
a pill rolling tremor, cogwheel rigidity & bradykinesia (or slow movement)
Tardine Dyskinesia (or TD) is uncontrollable facial tics, grimacing & tongue movements
As scary as these symptoms may look, they are generally not medical emergencies.
In most cases you will continue to use the drug with perhaps a reduction in the dose
or the addition of an anticholinergic mediation like Benzatropine or Diphenhydramine.
Tardive Dyskinesia is the exception and requires cessation of the medication as it can be permanent.
Usually you would switch a patient with TD to a 2nd gen antipsychotic.
Hyperprolactinemia is a side effect due to Blockage of Tuberoinfundibular dopamine.
It presents just like any other disease that increases prolactin.
So you can have galactorrhea, gynecomastia, decreased libido and menstrual irregularities.
These are not tested as often, but typical antipsychotics can also cause QT Interval
Prolongation & Anticholinergic effects such as sedation, orthostatic hypotension, dry
mouth, constipation etc.
Atypical Antipsychotics (AKA 2nd Generation Antipsychotics) block dopamine and serotonin
receptors meaning they treat positive and negative symptoms.
They also may have improved specificity which limits side effects when compared to typical
antipsychotics.
They are largely used as first line medications instead of the 1st generation antipsychotics.
You can still get all of the same side effects as you do with the typical antipsychtoics,
but at least in theory they should be much less common.
In particular Risperidone has a side effect profile closer to the typical antipsychotics
as it has EPS and hyperprolactinemia more commonly than the other 2nd gens.
Clozapine and Quetiapine are the least like the typicals as they essentially never have
EPS or high prolactin.
So if you are using a typical antipsychotic and have to switch meds based on the side
effects, Quetiapine is probably your best option.
Like some of the 1st Gens, most of the 2nd Gen Antipsychotics also commonly have sedation
as a side effect.
QT prolongation is another side effect seen in both classes.
It is especially common in Ziprasidone.
There are also side effects that are unique to Atypical Antipsychotics.
One of them is Metabolic Syndrome (diabetes, weight gain, hyperlipidemia etc.).
So patients on atypical antipsychotics should have their weight, blood pressure, blood glucose
and lipids monitored regularly.
Olanzapine & clozapine are the worst for causing metabolic syndrome so they should be avoided
in patients who have diabetes or obesity.
Ziprasadone and Aripiprazole cause metabolic syndrome less than the other 2nd gens.
Clozapine is the “prototype” for the atypical antipsychotics as it was the first one developed
and has higher efficacy.
However, it isn’t used nearly as much as the others because it causes agranulocytosis
and seizures.
This drug is usually reserved as a last resort if the other options don’t work.
Patients on Clozapine needs to have a CBC very frequently to monitor for agranulocytosis.
If a low WBC count is found the medication needs to be discontinued to prevent life threatening
infections.
Mood Stabilizers are a group of medications that help to steady and/or prevent intense
mood swings.
These medications are used primarily for Bipolar Disorder and Schizoaffective Disorder.
Many antipsychotic medications can have a mood stabilizing effect.
They are a first line treatment for mania when there are psychotic features and/or you
need a fast onset of action.
However, when we use the term Mood Stabilizer we are generally talking about Lithium and
anticonvulsants rather than antipsychotics.
Mood Stabilizers require gradual titration and take about 1 week to kick in so they are
not as useful in the acute setting.
However, for long term treatment they are often the treatment of choice for Bipolar
Disease.
A combination of an antipsychotic and a mood stabilizer is often used for Bipolar Disorder
as it usually works better than monotherapy for acute management and relapse prevention.
Lithium is the first line mood stabilizer according to most guidelines and textbooks,
but in practice many psychiatrists use other medications first due to better side effect
profiles and other considerations that make it easier to prescribe.
Lithium has a narrow therapeutic window which means dosing can be difficult and requires
close monitoring with Lithium Blood Levels (which correlate with efficacy).
The mechanism of Lithium is not very well understood.
Lithium Toxicity (AKA Lithium Overdose) may occur acutely from intentional or unintentional
large doses of lithium or chronically from a prescribed lithium dose that was not properly
titrated.
It can present with nausea/vomiting, diarrhea, tremors, altered mental status, incoordination,
and seizures.
If these symptoms arise the Lithium treatment should be discontinued immediately to prevent
fatal consequences.
Lithium is a teratogen that causes cardiac deformation in the fetus so it should not
be used in anyone who is or may become pregnant.
Lithium commonly causes Hypothyroidism.
They love to write questions about that.
Lithium is nephrotoxic and can cause Nephrogenic Diabetes Insipidus (thirst, polyuria etc.).
This is another super high yield point Before you start the medication and regularly
after initiation you should get a pregnancy test, thyroid level and creatinine test to
monitor for the onset of side effects.
That brings us to Anticonvulsants.
Some, but not all, epilepsy drugs can be used as mood stabilizers.
This includes Valproate or Valproic Acid, Carbamazepine and Lamotrigine.
These drugs are known to be hepatotoxic so regular liver function tests (LFTs) should
be performed.
A CBC should also be checked as these drugs can have hematologic effects such as Thrombocytopenia.
Valproate or Valproic Acid is the most commonly used anticonvulsant for Bipolar Disorder.
It is associated with spina bifida, so you have to give folate to patients if they are
trying to get pregnant.
It is also associated with pancreatitis.
Carbamazepine& Lamotrigine are alternatives.
They are associated with rashes and severe hypersensitivity reactions like Stevens Johnson
Syndrome.
They can also lead to an increased metabolism of the hormones is oral contraceptives and
unintentional pregnancies.
This is obviously a bad thing considering the drug is also a teratogen.
Next up is Anxiolytics.
This is a group of medications that relieve or abort anxiety.
SSRIs and SNRIs are considered first line pharmacologic treatment for Generalized Anxiety
and Panic Disorder.
We discussed these types of medication in depth in our previous video on antidepressants,
and most of them do have anxiolytic properties.
The only real difference is that higher doses are usually needed to treat anxiety than depression.
Cognitive Behavioral Therapy has similar efficacy to SSRIs/SNRIs and is also considered a first
line treatment.
The best treatment option may be a combination of an antidepressant with CBT.
The downside to both of these 1st line options is that they take about a month to start working.
Buspirone is another good anxiolytic while Benzos and TCAs are considered second line
medications.
Beta Blockers (like propranolol) are not true anxiolytics, but they can help mask some of
the symptoms of anxiety such as palpitations.
Buspirone (or Buspar) is another treatment option to consider for GAD, but it does not
work for Panic Disorder.
It is a non-benzo anxiolytic that functions by acting as a partial serotonin agonist.
It does not have the risk of dependence, abuse, or withdrawal like Benzos and does not have
nearly as much sedation.
However, Buspirone does take a couple weeks to kick in.
Benzos usually end in “Zepam” or “Azolam.”
They are broken down into short acting, intermediate acting and long acting groups.
However, short acting Benzos aren’t used as much and are lower yield for the exam so
I haven’t listed them.
The highest yield intermediate acting benzos are Lorazepam, Alprazolam & Temazepam.
The most important long acting benzodiazepines are Clonazepam & diazepam.
Benzodiazepines increase the effects of Gamma-Aminobutyric Acid (AKA GABA, an inhibitory neurotransmitter)
by increasing GABAs affinity for the receptor and increasing the frequency of the Cl channel
opening.
Benzodiazepines are great at aborting acute anxiety and panic attacks quickly.
They have a much faster onset of action than other anxiolytics.
However, Benzos don’t work very well to prevent anxiety and panic attack prophylactically.
Perhaps the best use for Benzos is in addition to an SSRI or SNRI.
You can start both together and then after about a month when the antidepressant has
started working you can taper off the Benzo.
Benzos are largely considered safe for short term use, but long term use is very controversial
due to the risk of abuse, dependence, sedation and withdrawal.
These medications are generally contraindicated in those with a history of substance abuse,
and use in elderly populations should be limited due to the increased level of risk of adverse
events.
Scheduled long acting doses are preferred, because as needed use of short acting benzos
has a higher risk for psychologic dependence.
My last video in the Psych section was on substance abuse and discussed things like
Benzo overdose and withdrawal, so go watch that one if you haven’t already.
I have also already covered the use of benzo for alcohol withdrawal so I won’t cover
that here.
Later when I make the neuro videos I will cover things like the use of Benzos for seizures
or status epilepticus.
Benzos also have action as Hypnotic medications and can be used for the short-term treatment
of insomnia.
However, their use should be limited to a few weeks duration due to the risk of dependence.
It is preferred that Benzos be used intermittently and at the lowest effective dose.
Higher doses of Benzos are needed for a Hypnotic effect when compared to anxiolytic action.
There are also non-benzo hypnotics that are at least in theory safer options for long
term use.
This would include drugs like Lunesta and Ambien, but this topic is very low yield for
the Step 1 exam so I will skip it.
That brings us to the end of the video.
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Thanks so much and good luck studying.