CNS & Psychiatric Drugs Flashcards
(31 cards)
What kind of antianxiety/antidepressant is your patient likely to be taking if they need to avoid eating foods like avocados, cheese, liver, fava beans, and chianti?
Monoamine oxidase inhibitors (MAOIs)
Are there any dietary restrictions for MAO-B inhibitors?
No, even though the MAO-B subtype metabolizes tyramine, there are no dietary restrictions except when taken at very high doses.
For which antidepressants can overdose be lethal?
MAOIs, TCAs
but not SSRIs
What are some side effects of overdose of MAOIs?
tachycardia, hyperthermia, hypermetabolism (including rigidity), seizures, coma
What may be used as treatment of MAOI overdose?
Dantrolene (muscle relaxant, also used for MH)
Should MAOIs be stopped prior to anesthesia?
No, there is no data to support stopping for 2-3 weeks prior to anesthesia.
What are some possible drug interactions you may want to consider in the OR when your patient is on MAOIs?
- Sympathomimetics should be used with caution (use direct > indirect)
- Consider avoiding epi in local/regional anesthetics
- Opioids have a potential for excitatory OR depressive reactions w/ meperedine.
What drug do we give as treatment of choice for bipolar (manic-depressive) disorder?
Lithium
How do we dose lithium?
It requires the measurement of plasma concentrations.
Where is lithium reabsorbed?
As it is filtered by the kidney, it gets reabsorbed in the proximal tubule, competing with sodium.
What does dehydration or diuretics do to lithium levels?
Sodium depletion may increase the levels of lithium.
What are some side effects of lithium?
polydipsia, polyuria, hypothyroidism
What are some drug interactions associated with lithium?
- prolonged responses to depolarizing AND nondepolarizing NMBs
- Avoid diuretics (loop, thiazide) & NSAIDs
- Neuroleptic drugs can increase risk of extrapyramidal side effects and NMS
What are symptoms of lithium toxicity?
lethargy, weakness, tremor, QRS widening, heart block, hypotension, confusion, seizures.
What causes exacerbation of lithium toxicity?
dehydration, sodium restriction, diuretics, NSAIDs, dialysis
What is given as treatment of schizophrenia primarily, with some affect on bipolar disorder?
Antipsychotic drugs (neuroleptic)
Haloperidol (Haldol) & droperidol are most common.
Others: Chloropromazine (Thorazine), clozapine (Clozaril), risperidone (Risperdal)
What is the mechanism of antipsychotic drugs like Haldol?
They block the dopamine receptors
How are antipsychotic drugs metabolized?
Hepatic metabolism
What are the side effects of antipsychotic drugs?
- Extrapyramidal effects like movement disorders (all except clozapine)
- Neuroleptic Malignant Syndrome
- CV effects
- Endocrine effects
- CNS effects
- Agranulocytosis (Clozapine)
Describe the extrapyramidal effects of antipsychotic drugs.
- Tardive dyskinesia: abnormal involuntary movements of face, neck, tongue
- Acute dystonic reaction: muscle rigidity/cramping of face/neck/tongue, larynx
- Parkinsonism: Rigidity, tremor, bradykinesia/akinesia
- Akathesia = restlesness
What can you give for an acute dystonic reaction?
diphenhydramine (Benadryl) or benztropine (Cogentin) – Anticholinergics
What are symptoms of NMS (neuromuscular malignant syndrome)?
hyperthermia, muscular hypertonicity, autonomic instability, mental status changes, and rigidity leading to possible vent requirement or myonecrosis (renal failure)
What is the incidence of NMS w/ Antipsychotic drugs?
0.5-1%
What are the mortality rates of NMS with antipsychotic drugs?
20-30%
