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Psychiatry – High Yield Pharmacology

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Topics in this video are: anti-depressants, TCA, mirtazapine, first generation antipsychotics, second generation antipsychotics, lithium, carbamazepine, lamotrigine, neuroleptic malignant syndrome, serotonin syndrome, malignant hyperthermia, EPS and treatments, and more

In this video let’s talk about high-yield pharmacology related to psychiatry so lithium is our first line agent for bipolar disorder but it comes with a lot of side effects which are important to know so epstein’s anomaly is when there’s apical displacement or right atrialization of the right ventricle that basically means the tricuspid valve and the right atrium

Dips down into the right ventricle so you don’t want to give lithium to people who are pregnant lithium can also affect the thyroid so it’s important to keep an eye out on tsh and t3t4 levels as well so lithium also has a very low therapeutic index so you want to check their renal function because lithium is excreted by the kidney also very high yield to nose

Interaction of lithium and a couple different other medications the patient is taking thiazides ace inhibitors or nsaids that can cause an increase in lithium levels and then causing toxicity and lithium toxicity is going to present with gi symptoms so nausea vomiting diarrhea abdominal pain as well as neurological symptoms so that’ll be like confusion ataxia

Agitation maybe a tremor another mood stabilizer very commonly used for bipolar is alpharic acid and valproic acid is metabolized by the liver so since it’s metabolized by the liver you want to check lfts pretty routinely at least for the first six months while broke acid can also cause pancreatitis thrombocytopenia and alopecia are other common side effects as

Well you shouldn’t give up acid in pregnant women either because it has a high risk of neural tube defects in the baby lamotrigine is another mood stabilizer you can use and with this important to watch out for stephen johnson syndrome carbamazepine is another mood stabilizer and again this can cause sjs also with carbon monoxide watch out for thermocytopenia

Check your lfts and carmezamine is also tetragenic and metabolized by sip 450. so that’s a good sign going to talking about sip 450 inducers which are caramazipine st john’s wort and even tobacco and some sip 450 inhibitors that are good to know are floccitine paroxetine dualocity and circulene which are all ssris or snris it’s very important to remember that you

Don’t give someone with bipolar antidepressants because that can induce medias before starting an antidepressant make sure you screen them for bipolar disorder so our first line treatment for depression is ssris when you start someone on ssri the most common scientific people complain about is gi symptoms such as nausea vomiting they can also have some insomnia

When they first start ssri but then they should develop tolerance after a couple weeks if they abruptly discontinue their ssr they can get like illness it’s also important to remember that ssris can actually increase suicidal ideation in young people less than 25 years old initially when they first start taking it so it’s really important to monitor them closely

And it’s important to remember that a patient needs to be on the medication for at least four to six weeks for an appropriate therapeutic child before trying another ssri and they have to try to accessorize before switching classes for depression treatment ssris can increase warfarin levels so that can cause more bleeding specifically fluoxetine has the longest

Half-life so when you’re switching from ssri to like an maoi you need a washout period so fluoxetine since it has the longest half-life it specifically requires at least a five week washout period cetalopram or escitalopram be careful with qt prolongation or giving this drug to anyone who’s had an mi in the past or heart issues in the past ssris can come with a

Lot of side effects such as decreased libido and delayed ejaculation so ssrs can actually use for treatment for premature ejaculation but let’s say a patient’s having a lot of sexual side effects and they don’t want to take an ssri you can get them buproprion which is norepinephrine and dopamine reuptake inhibitor be careful not to give this to anyone who has an

Eating disorder more prone to vomiting or history of seizures you can also give them mertazapine for example which is an alpha 2 blocker so because of that i can cause hypotension but you can also give mertesapen in patients that are not eating a lot because it increases their appetite if they need to gain some weight or if they also are having trouble sleeping

Trazadone is another drug you can use for depression the side effect for this is prasm orthostatic hypotension and usually people will give someone trouble especially if they need more help sleeping snris include duloxetine and venlafaxing snrs are great in people who also have like diabetic neuropathy for example it’s important to know that venlafaxie will cause

Increased blood pressure and duloxetine is a side effect of hepatotoxicity tcas can also be used for depression if ssris don’t work drugs in this category include amitriptyline imepramine disappear amine clomipramine but it’s important to remember that immembramine is used to treat for bed wetting in children um clone membrane is used for ocd amitriptyline is often

Used for chronic pain as well migraines insomnia if you have a tca overdose you treat that with sodium bicarb uh mechanism action of tca is serotonin norepinephrine we uptake inhibitor side effects include anticholinergic properties so dilated pupils being really hot having flushed or dry skin maois are not very commonly used for depression anymore but they are

A category of drugs that can treat it but with maoi drugs it’s important to remember the tyramine crisis so if the patient is having wine and cheese for example this medication that’ll induce that they’ll become very hypertensive and also miois has serotonin properties so also risk factors for serotonin syndrome if they don’t have an appropriate washout period or

Taking other drugs that have serotonin properties other drugs to watch out that do have serotonin properties are linozolid tca organ dan centron eusperone and if someone has serotonin syndrome they’re going to present with sweating hypertension tachycardia hyperreflexia hyperactive bowel sounds they’re going to have lower extremity rigidity they can have myoclonus as

Well treatment for this and is to stop the medications and give them ciproheptidine and then the other syndromes that kind of appear similar are malignant hyperthermia which occurs after someone has had anesthetics neuroleptic malignant syndrome is nms that occurs after someone’s had antipsychotics and if you have nms you’re going to present again with fever you’ll

Have diffuse lead pipe rigidity and we’ll probably have elevated creatinine kinase treatment for nms is bromocriptine and dantrolene nms most commonly occurs with first generation antipsychotics but it can occur with any antipsychotics so our low potency first generation are clomiprazine and thyroidizing thyroidizine causes like retinal pigmentation so the r and

Thyrozine is for retinal and clomiprazine so the c is for cornea your first generation high potency or haloperidol flufenazine and these are gonna also cause more epsom you treat tartar dyskinesia with these drugs listed down here you treat academia which is a restlessness with beta blockers benzos and ben stripin you treat dystonia with benadryl which is different

Hydramine or benztropine now for second generation antipsychotics again these block dopamine and serotonin they have more of a risk of metabolic syndrome overall especially clozapine and olanzapine are the two that really cause you to gain weight clozapine is used for treatment resistant schizophrenia and because it has the severe side effect of agranulocytosis or

Neutropenia if their anc drops below 1 500 you have to stop the drug other side effects are also hypersalivation constipation having an ileus is very common or myocarditis ziprezadone can cause qt prolongation or lines of people talk about weight gain dyslipidemia hyperglycemia sedation it can also be used for sleep protiope is another one that’s a good one for

Sedation risperidol will increase prolactin with a tubular infundibular pathway all antipsychotics can lower the seizure threshold and again all these antipsychotics because you’re bringing down your dopamine levels can cause some parkinsonian side effects as well such as like bradykinesia rigidity tremor so you can treat this parkinsonianism with amantadine or

Venstropine it’s also important to remember that dopamine inhibits prolactin so if you’re blocking dopamine you have more prolactin which is why a lot of these will have the gynecomastia increased prolactin side effect also tsh can increase prolactin so hypothyroid patients for example will have more tsh and that can also induce more prolactin so let’s talk about

Benzodiazepines it’s important to know which ones are short acting which go by the mnemonic of atom atom so alprazolam lorazepam oxazepam and temazepam then it’s good to know the ones that are not processed by the liver so you can get this at people who have cirrhosis alcohol use disorder anything causing liver conditions and so these ones would be the ones that

Start with o t and l so the mnemonic is outside the liver so oxacan lorazepam and temazepam let’s say someone has a benzodiazepine overdose you should give them flumazinil flumazanil is a gaba antagonist for alzheimer’s the main drug category to use are acetylcholine esterase inhibitors so acetylcholine esterase is the enzyme that breaks down acetylcholine so you

Don’t want to break it down because you want to increase the levels of acetylcholine patients with alzheimer’s the drugs that do this are donepazil galantimine and rivastigmine you can also use another drug called memantine and this is an nmda or glutamate receptor antagonist

Transcribed from video
Psychiatry – High Yield Pharmacology By Dr Sheela