March 22, 2023

Distinguished future physicians welcome to stomp on step one the only free video series that helps you study more efficiently by focusing on the high iso material i’m brian mcdaniel and i will be your guide on this journey through antidepressants this is the eighth video in my playlist covering all of psychiatry for the step one medical board exam we are going

To review the mechanisms indications and side effects for the various antidepressant classes including tricyclic antidepressants ssris snris and atypicals i originally planned on having antipsychotics anxiolytics and mood stabilizers in this video also but it was getting way too long so i split those meds off into their own video which which will be next in the

Series it is tough to break the high yield rating down by subclass like i usually do so this time i will just give you the high yield ratings for all the antidepressants at once overall antidepressants get a high yield rating of nine for the step one medical board exam this means based on a number of factors including the frequency of appearance on the retired

Step one questions you are almost definitely going to see at least one question on the exam about antidepressants by far the most important aspect is the side effects for these medications most questions are going to be about ssris and tcas so focus your attention there maois are very old rarely used anymore and unlikely to show up on the exam but you may see

Them in older practice tests i’m going to focus on pharmacologic treatments for depression because that is what the test questions are on but remember there are alternatives to meds cognitive behavioral therapy and counseling can have similar efficacy to medications using meds and cbt together is the best option also electroconvulsive therapy or ect has even

Better results and faster onset than medications but the stigma for ect and common side effect of amnesia means that it is usually only used in severe depression with patients who can’t tolerate medications i will start with some general principles that apply to all the antidepressants and then we will talk more specifically about each class one hypothesis for

The pathophysiology of depression is that is due to low levels of monoamine neurotransmitters mainly serotonin norepinephrine and dopamine that is why antidepressants aim to increase the levels of these neurotransmitters in the synaptic cleft they do this by slowing the reuptake of the neurotransmitters so that they stay in the cleft longer and interact with the

Postsynaptic receptors more often the first drugs in this group were non-specific and increased all of the monoamines which leads to a lot of side effects and safety issues related to toxicity newer antidepressants are more selective and mostly only affect the reuptake of one or two monoamines unfortunately antidepressants take at least a month to start working

Good patient education about the delayed onset of effect and close monitoring of the patients during this initial period is extremely important patients can become hopeless if they expect the drug to start working right away this may be one of the reasons why antidepressants are associated with suicide especially in patients 25 years and older another proposed

Mechanism is that the depressed person may have the energy to carry out their suicide once the medications start to work there is now black box warning for suicide on antidepressants some psychiatrists argue that they don’t actually see this association with suicide in clinical practice and that the thing that really increases the risk for suicide is not treating

A depressed patient with the proper medications however it’s still standard practice to have a close follow-up with patients you are starting on antidepressant usually this will involve a follow-up visit about two weeks after the medication is started at this visit the drug will not have started working yet so you can’t evaluate efficacy but you can monitor for

Side effects like suicidality another serious side effect you have to be on the lookout for soon after initiating treatment is mania if a bipolar individual is incorrectly diagnosed as having depression an antidepressant may induce a manic episode another very serious side effect that has to be considered for antidepressants is serotonin syndrome this usually

Occurs when you combine multiple antidepressants at the same time or combine an antidepressant with another medication that increases serotonin such as dextromethorphan or an opioid it presents with tremor diaphoresis tachycardia flushing and hypertension if not corrected it can progress to delirium altered mental status and death treatment includes medication

Cessation and the use of ciproheptidine a serotonin antagonist in order to prevent this from happening you should have about a month wash out period when you are switching between antidepressants so you taper the first medication down and then stop it give the patient at least a month with no antidepressant and then start adding the new medication slowly most

Side effects begin immediately after starting the medication but diminish over the course of about a month a principle that applies to all of the antidepressants is start low and go slow this means that you start with a lower dose and slowly increase it in order to decrease the side effects and increase patient compliance the dose you start the patient on may not

Even be at a therapeutic level but every month or so you can increase the dose a little bit everyone reacts differently to antidepressants some will initially be partial responders or non-responders to certain drugs that you prescribe oddly patients may react differently even to drugs within the same class for example one ssri may work great for a patient while

Another ssri does nothing for them this is why treating depression is sometimes a trial and error process since there is a delayed onset of effect you usually work your way up to the max dose and wait for about six weeks before switching to another medication about half the people who have their first depressive episode will eventually relapse and have another

Episode of depression therefore treatment is usually continued for at least a year after the first episode of depression after two to three episodes of depression the odds of having another depressive episode are so high that most docs would treat with antidepressants for life most antidepressants can have a withdrawal effect if they are discontinued abruptly

It can present with a wide variety of symptoms including insomnia flu-like symptoms and change in mood antidepressants with short half-lifes like paroxetine more commonly have withdrawal effects to prevent withdrawal most antidepressants should be tapered before discontinuation so we will start with the tricyclic antidepressants or tca the most high-yield meds

For this class are amitriptyline nor tryptolene amid bramine clomipheramine and doxepine it is easy to remember because almost all the drugs in this class even those that i didn’t specifically list end in iptaline or ipramine tricyclic antidepressants tcas block reuptake of norepinephrine and to a lesser extent serotonin they are more selective than the very old

Maois but not as selective as ssris and snris this is why they’ve largely been replaced by ssris snris as first line depression treatments they are still used to treat depression resistant to other antidepressants as well as off-label use for a number of other conditions including fibromyalgia chronic pain and neuropathic pain and enuresis a loss of control of

Urination such as bedwetting if a patient has depression and something like chronic pain syndrome this should be your first choice side effects limit the use of tcas the most common side effects fall under the category of anticholinergic depending on the specific side effect you may be able to more specifically describe these as anti-muscarinic antihistamine or

Anti-adrenergic effects they include dry mouth blurry vision urinary retention constipation sedation orthostatic hypertension and cognitive impairment these symptoms are not nearly as common in newer antidepressants like ssris insomnia weight gain and sexual dysfunction are also common side effects there are also rare but very serious cardiac adverse reactions

Tcas can cause qt interval prolongation which is why they are contraindicated in those with underlying conduction abnormalities and recent mi and ekg should be done before starting patients on tcas tcas are also fatal in overdose due to arrhythmias this is very risky considering that antidepressants are given to a group of individuals who may be suicidal tcas

Are correlated with seizures and coma while also interacting with many different drugs via their metabolism via cytochrome p450 selective serotonin reuptake inhibitors increase serotonin in the synaptic cleft by decreasing their reuptake they are selective because they have less effect on the reuptake of other monoamines like norepinephrine and dopamine they

Are first-line treatment options for depression ocd social phobia ptsd generalized anxiety eating disorders and other psychiatric conditions they are used for so many different things that if you get stuck on a psych med question and you don’t know the answer just selecting the ssri is probably the safest bet here is the list of the most commonly tested ssris

Paroxetine gluoxetine sertraline cetalopram and escitalogram i’ve included the brand names for each but remember only generic names will be tested on the exam each of these has slightly different indications and efficacy but in general you can get questions right by just knowing the general characteristics of the entire group they have become the first line

Medication for depression as they have a better safety profile and suit fewer side effects than tcas unlike tcas ssris are usually not fatal in overdose that is obviously a big advantage when you are treating depressed patients that may be suicidal ssris can also have gi problems nausea diarrhea etc headaches and insomnia as side effects these adverse reactions

Will usually diminish over time but if insomnia persists tracidone is sometimes added to an ssri to lessen the insomnia side effect the most common side effect is sexual dysfunction which can include anorgasmia diminished libido and erectile dysfunction thankfully this side effect can largely be eliminated by combining an ssri with bupropion the sexual side

Effects can also be a plus for some patients as ssris are sometimes abused or used off-label to treat premature ejaculation ssris are also associated with bleeding as they can interact with anticoagulants like warfarin serotonin norepinephrine reuptake inhibitors have a similar mechanism to ssris but they block the reuptake of serotonin and norepinephrine other

Than that snris have very similar indications efficacy and side effects as ssris so i will not spend much time specifically on snris the most commonly used snmris are duloxetine venlafaxine and desvenlifaxine that leaves us with the atypical antidepressants their efficacy side effects and indications are similar to the drugs that we have already discussed but

There are a couple unique features with each that we need to point out they work by slightly different mechanisms than the other medications but that is low yield so i’m not going to cover that the highest yield medications in this group are bupreon tracidone and mertazapine the euproprion or wellbutrin does not have sexual side effects and may actually increase

Sexual function this is why bubreon is often added to ssris because it counteracts the sexual dysfunction of ssris another important thing to know is that proprion can be used off label for smoking cessation so if you have a patient who is depressed and wants to quit smoking this is the clear choice a downside to this drug is that it lowers the seizure threshold

Especially in those that are bulimic so this medication is contraindicated in people with a history of eating disorders and epilepsy trazadone is almost never used purely as an antidepressant anymore because the side effects of sedation is so strong however trazadone is commonly used off-label as a sleep aid or in conjunction with an ssri if they are having

Insomnia the rare but dangerous side effect for this drug to remember is pribism this is a prolonged direction that can lead to impotence if not treated some people remember the side effect by the pneumonic trasia bone the only high yield thing to remember for ritazapine or is that it commonly has weight gain this may actually be a positive thing if you’re treating

Depression in somebody like a frail elderly patient that needs to gain weight that brings us to the end of this video if you found it useful and want to find more videos easily you can click on this warn subscribe button here which also helps me out a lot our next video and the last video in the psychiatry section is going to cover antipsychotics mood stabilizers

And anxiolytics to be taken directly to that video you can click on this black box here if you’re watching on a computer thank you so much for watching and good luck with the rest you’re studying

Transcribed from video
Antidepressants SSRI, SNRI & Tricyclic Antidepressatns Citalopram Prozac Amitriptyline By Muwanika Hussein