Psychiatric Drug Flashcards
How long before the antidepressants take effect?
Clinical Onset often takes up to 2 weeks
What are the types of antidepressants
- Tricyclic Antidepressants (TCA)
- Selective Serotonin ReUptake Inhibitors (SSRI)
- Atypical Agents
- Monoamine Oxidase Inhibitors
MOA of TCA
whats the common uses
samples of TCA
Mechanism of action
- Inhibit synaptic reuptake of norepinephrine and serotonin
- Variable antagonist activity at histamine, anti-muscarinic acetylcholine, α1 adrenergic, NMDA, μ1-opioid receptors, sodium channel blockade
Common medications
- Amitriptyline
- imipramine
- desipramine
- doxepin
- nortriptyline
Common uses
- Depression, chronic pain (neuropathic and fibromyalgia), some forms of acute pain
- Use decreasing due to side effects
What are the common side effects of TCA
- Postural Hypotension
- Urinary retention
- blurred vision
- dried mouth
- Hypotension - common
- QTC prolongation
- DELIRIUM - CHOLINERGIC DEFICIENCY
- SEROTONIN SYNDROME
- NARROW THERAPEUTIC INDEX
drug class that has a narrow therapeutic index
what are the changes that you can see?
TCA
Narrow therapeutic index
- Can cause EKG changes particularly with overdose; non-symptomatic EKG changes will subside with time
- Flattening/inversion of T waves, widening of QRS complex, prolongation of QT interval, bundle branch block, premature ventricular contractions, conduction abnormities, ventricular arrhythmias
Reduction of seizure threshold (dose-dependent) – Caution use with tramadol or meperidine
Serotonin syndrome
- Avoid use with MAO-I – inhibit breakdown of neurotransmitters (i.e., dopamine, serotonin, norepinephrine)
What effect will chronic TCA use have with pressors
-
Decreased response to sympathomimetics with chronic (>6 weeks) TCA use [MORE DRUG TO GET APPROPRIATE RESPONSE]
- Adrenergic receptors are sensitized, downregulation of β receptors or catecholamine stores depleted
What effect will acute TCA use have with pressors
Sympathomimetic agents
- Exaggerated response of sympathomimetics with new TCA starts – Increased amount of catecholamines present to stimulate post-synaptic receptors due to norepinephrine reuptake blockade
What effect will TCA use have with the induction of anesthesia
- Possible increased incidence of cardiac dysrhythmias (mostly with halothane)
you have a patient on TCA. which drug for N/V when given may cause excessive sedation?
Anticholinergic agents (i.e., diphenhydramine,
scopolamine)
- Additive side effects with anticholinergic drugs –> increased risk for excess sedation, postoperative delirium, confusion
Why would there be an augmented analgesic and ventilatory effects of opioids when used with TCA?
Because TCA has CYP450 inhibition
–> may increase opioids and sedatives in the system
SSRI MOA
Mechanism of action
– Major mechanism: inhibits the reuptake of serotonin
– Minor mechanisms:
- Inhibits norepinephrine reuptake
- Inhibits dopamine uptake
- Histamine, musarinic receptor antagonist
SSRI that has an active metabolite
Fluoxetine
* maybe given to a patient without parenteral access and liver dysfunction because of an active metabolite and long half-life (1-4 days)
Your patient on Fluvoxamine has been NPO for 45 hours (2ish days). what can you expect?
You may see withdrawal symptoms
* Fluvoxamine has the shortest half-life among SSRIs (15 h)
SSRI common SE
*Should not have much SEDATION
QTC prolongation
*lesser effects when it comes to sedation as compared to TCA
SSRI: FLUOXETINE
ADVERSE SE
- BRADYCARDIA
- SYNCOPAL OCCASIONAL OCCURENCE IN ELDERLY PATIENTS
What can you expect in an SSRI withdrawal?
when do you see it?
- Dizziness,GI complaints,flu-like symptoms,anxiety, insomnia, paresthesias, myalgia, visual disturbances
- Requires atleast ~1month therapy to be at risk
- More severe with shorter acting agents paroxetine,Fluvoxamine)
- Seen within 1-7days after discontinuation
- Taper before discontinuation
Serotonin Syndrome
– Avoid use with MAO-I or have an adequate washout
– Cautious use with drugs with MAO-I properties(i.e, opioids, linezolid, methylene blue)
– Have adequate washout of the drug from the system if possible
MIRTAZAPINE
POTENT ANTAGONIST OF
- Potent antagonist of 5-HT2 and 5-HT3 serotonin receptors and H1 histamine receptors
- Moderate peripheral α1 adrenergic and muscarinic antagonist
NE:SE reuptake inhibitors
SE
decrease seizure threshold
TRIAZOLOPYRADINES
sample agents
used for insomnia
where is it metabolized?
SE?
Agents
- trazodone
- nefazodone
Mechanism of action
- Serotoninreuptakeinhibition
- α1 antagonist, histamine antagonist
Hepatic metabolism through CYP450
- +activemetabolites
- Inhibits CYP450
Common adverse effects
- Qtc Prolongation
- Sedation
Anesthesia considerations in patients receiving SSRI
SIGNS OF Serotonin Syndrome
when does it occur?
what is the tx
what is the ideal washout period before starting MAOI inhibitor?
Signs of serotonin syndrome (occurs within 24h)
- Hyperthermia[fever!!], confusion, agitation, autonomic hyperactivity, myoclonus, hyperreflexia, diaphoresis, tremor, diarrhea, neuromuscular abnormalities, ocular clonus
- Treatment: stop offending agent + begin supportive care + serotonin antagonists
- Serotonin antagonists: cyproheptadine –
Prevention
• Ideal washout period before starting MAOI inhibitor is 14 days
If your patient got codeine, what can happen to it when given with SSRI?
SSRI can inhibit the metabolism of Codeine to morphine
- may get inadequate analgesia
DRUGS THAT INCREASE THE RISK OF SEROTONIN SYNDROME WHEN GIVEN WITH SSRI
- Antiemetic (metoclopramide, ondansetron)
- Fentanyl
- Linezolid
- Meperidine
- Methadone
- Tramadol
- Valproic acid
SE OF BUPROPRION
SEIZURE RISK
MAOI SE
SEDATION
THE FACT THAT THERE ARE DRUG INTERACTION!
How long is the duration of MAOI inhibition?
10 - 14 days
MAO- I
- what does it do to tyramine
How will MAOIs affect vasopressor effects?
May increase risk of vasopressor effect and hypertensive crisis
- Inhibits systemic clearance of catecholamines via inhibition of MAO- dependent degradation
- May need to use 1/3 of the normal dose of vasoactive medication
What drugs should you absolutely AVOID with MAOI?
burn this in your brain
MEPERIDINE AND TRAMADOL
LITHIUM
MOA
What is the goal?
Goal cerum concentrration
(maintenance)
0.6 - 1 meq/L
LITHIUM
CHRONIC SIDE EFFECTS
CHRONIC SIDE EFFECT
- Nephrogenic diabetes insipidus
- Polyuria/ polydipsia
- Hypothyroidism
- Myxedema coma
LITHIUM
ACUTE OVERDOSE
- Nausea, vomiting, diarrhea
- Confusion
- Tremor
- Myoclonus
- Seizures
- Coma
- T-wave inversion Ventricular arrhythmias
Conditions that are contraindicated with Lithium
may increase lithium toxicity
Renal Insufficiency - highly renally cleared
Hyponatremia
90% of Li+ is reabsorbed in proximal convoluted tubule and competes with Na+ reabsorption
DRUG INTERACTIONS pertinent to anesthesiology
mostly risk for AKI
so be careful with diuretics
What did Mona say about Typical Antipsychotics?
that they are not much used anymore– probably just Haldol
only because it’s very convenient
its IV and can also be given IM
what do Antipsychotics block?
MOA?
everything.
Mechanism of action
- Blocks histamine, α1 , cholinergic, dopamine, serotonin receptors to varying degrees
- Typical antipsychotics
- High D2 antagonism and low 5-HT2A antagonism
- Atypical antipsychotics
- Moderate to high D2 antagonism and high 5-HT2A antagonism
How ARE Antipsychotics
Metabolized?
LIVER JUST LIKE EVERYTHING ELSE
extensive CYP
hALF LIFE 18-40 HOURS
Antipsychotic side effects
what do you worry about?
WHAT ARE THE TREATMENTS?
TD
DY
AKA
PARK
movement type of disorders
Tardive dyskinesia occurs in up to 20% of patients taking antipsychotics for >1 year
- No treatment (anticholinergics worsen symptoms)
Dystonia occurs in ~2% of patients within first 72 hours
- TREATMENT:*** Response quickly to ***IV diphenhydramine 25-50 mg, Benztropine 2 mg, dose reduction/drug avoidance
Antipsychotics: Extrapyramidal side effects
Akathisia
- Treatment: propranolol 20-120mg/day(generallyfirstline), benzodiazepines, anticholinergic (benztropine), amantadine or clonidine
Parkinsonism
- Treatment : dose reduction/drug avoidance and anticholinergic (benztropine)
TREATMENT FOR TARDIVE dyskinesia
No treatment (anticholinergics worsen symptoms)
TREATMENT FOR DYSTONIA
Dystonia occurs in ~2% of patients within first 72 hours
TREATMENT: Response quickly to IV diphenhydramine 25-50 mg, Benztropine 2 mg, dose reduction/drug avoidance
TREATMENT FOR AKATHISIA
Akathisia
Treatment: propranolol 20-120mg/day (generally first line), benzodiazepines, anticholinergic (benztropine), amantadine or clonidine
TREATMENT FOR PARKINSONISM
Parkinsonism
Treatment : dose reduction/drug avoidance and anticholinergic (benztropine)
a rare but fatal condition resulting from abrupt dopamine blockade
NEUROLEPTIC MALIGNANT SYNDROME
May occur even after discontinuation of antipsychotics especially if long acting depot agents are used
- high fever and profound muscle contraction
- rigidity
rhabdo
SEVERE NEUROLEPTIC MALIGNANT SYNDROME CAN BE TREATED WITH?
DANTROLENE IV
*pt might be unable to take PO medications
DRUGS THAT WILL INCREASE THE RISK fOR MALIGNANT HYPERTHERMIA
- Malignant hyperthermia associated with anesthesia and with central anticholinergic syndrome may mimic neuroleptic malignant syndrome
- Additive effect with sedating medications
- QTc prolongation (common drugs used perioperatively)
Where are benzos metabolized?
If you have a pt that was on benzos before their liver resection, what should you consider before restarting the medication?
LIVER
* THINK BEfore you start the same dose that they are at home
* LIVER DYSFUNCTION –> RESP. DISTRESS, EXTRA SEDATION
Anesthesiology considerations in patients receiving benzodiazepines
- Additive effects with other sedating agents
- Increase sensitivity in elderly patients
- Careful with dosing in patients after hepatectomies or with new onset liver dysfunction
- Delirium associated with benzodiazepines
- Abrupt stopping of chronic therapy can precipitate withdrawal
- May cause prolonged sedation
- Perform careful medication reconciliation
