psychiatry medications

examples of SSRIs (selective serotonin reuptake inhibitors)

- Fluoxetine (Prozac)

- Sertraline (zoloft)

- Citalopram (celexa)

what causes depression?

deficiency of synaptic neurotransmitters (ex: serotonin (5-HT))

SSRI MOA?

bind to re-uptake transporter preventing removal of 5-HT (serotonin) increasing availability of 5-HT

-elevates mood and reduces anxiety

how long does it take for SSRIs to reach max effects?

4-6 weeks

do SSRIs have long or short half lives?

long

-once a day administration

which SSRI has the longest half-life?

Fluoxetine (Prozac)

-active metabolite (>100 hr half-life)

what does the long half life of fluoxetine increase risk of? decrease risk of?

-increased risk of drug interactions and fading of adverse effects

-decreased risk of withdrawal or rapid changes in mood

SSRIs indications for use?

-major depressive disorder

-obsessive compulsive disorder

-generalized anxiety disorder

-panic disorder

-bulimia nervosa

SSRIs absolute contraindication?

MAOI use within 14 days

what serious side effect does concurrent MAOI use increase risk of with SSRIs?

serotonin syndrome

-must have washout period of 1-2 weeks in between use

SSRIs non-serious side effects?

-sexual dysfunction

-GI distress (serotonin receptors in gut, affect motility) = N, V, constipation

-agitation

-tremor

-insomnia

specific side effects related to fluoxetine (prozac)?

tremor and insomnia

specific side effects associated with citalopram (celexa)?

prolonged QT interval, dose dependent

-not recommended for use in pts at risk for ventricular tachycardia

additional serious side effects of SSRIs?

-bleeding risk

-suicide

do patients need monitored on antidepressants?

yes

-all ages but those <25 may be at inc. risk for behavioral adverse reactions

SNRI (serotonin noradrenaline reuptake inhibitors) examples

- venlafaxine (effexor)

- duloxetine (cymbalta)

SNRIs MOA?

Blocks reuptake of serotonin (5-HT) and noradrenaline (NA)

note about venlafaxine?

low doses only affect serotonin reuptake

-must inc. dose to affect noradrenaline as well

note about duloxetine?

potent in blocking reuptake of both serotonin and norepinephrine equally

do SNRIs have shorter or longer half-lives than SSRIs?

shorter elimination

-consistency of taking drug is key for effects

what form of Venlafaxine is preferred for use?

extended release

-fewer side effect complaints

SNRIs indications for use?

-depression

-generalized anxiety disorder (GAD)

-social anxiety disorder

-panic disorder

absolute contraindications for SNRIs?

concurrent use of MAOIs

-risk of serotonin syndrome; 2 week wash period

side effects of SNRIs?

-GI distress (nausea, constipation) (MC with start)

-dizziness (w start and tapering)

-somnolence

-insomnia

-sexual dysfunction

-sweating

-inc. intraocular pressure

-tremor

-sustained HTN (dose related)

what must you do when discontinuing an SNRI?

low and slow gradual taper

-reduce risk of discontinuation sx (aggression, agitation, convulsions, etc.)

NDRIs (Noradrenaline and Dopamine Reuptake Inhibitors) example?

Bupropion (wellbutrin)

-zyban for smoking cessation

NDRIs MOA?

inhibit presynaptic reuptake of dopamine (DA) and noradrenaline (NA)

what are NDRIs classified as?

atypical antidepressants

how do NDRIs work to help smoking cessation?

block nicotinic receptors, preventing exogenous nicotine from binding, decreasing reward that smokers gain from nicotine

what neurotransmitter is most associated with addiction (relating to smoking)?

dopamine

indications of use for NDRIs?

-depression

-smoking cessation

**NOT used for anxiety

contraindications for NDRI use?

-history of seizures or those prone to seizures

-concurrent MAOI use (risk of hypertensive crisis)

-concurrent thioridazine use (atypical antipsychotic - risk of ventricular arrhythmias & SCD)

side effects of NDRIs?

-dry mouth

-nausea

-insomnia

-seizures

what side effect is not seen in NDRIs that is seen more commonly with use of SSRIs/SNRIs?

sexual dysfunction

-NDRIs don't affect serotonin

TCAs (tricyclic antidepressants) examples?

-amitriptyline (elavil)

-nortriptyline (pamelor)

where are TCAs metabolized?

liver

TCAs MOA?

block reuptake of norepinephrine and serotonin

do all TCAs work equally?

No

-degree of reuptake differs among agents

what additional affect to TCAs possess?

anticholinergic

-block H1-histamine (cause sedation) and alpha-adrenergic receptors

anticholinergic side effects related to TCA use?

-urinary retention

-benign prostatic hyperplasia (BPH)

-glaucoma (closed angle)

-increased IOP

when are TCAs fatal?

overdose situations

-one of the highest mortality rates associated with use

TCAs indications of use?

-depression (endogenous, reactive, and related to alcohol/cocaine withdrawal)

-obsessive compulsive disorder

-panic disorder

-neuropathic pain (specific to TCAs)

contraindications for TCAs?

concomitant use with MAOIs

-risk of serotonin syndrome

during recovery phase of an MI

side effects of TCAs?

-dry mouth

-confusion

-urinary retention

-constipation

-blurred vision

-increased IOP

-photosensitivity

-neurologic (delusions, hallucinations, aggressiveness, mania-like symptoms, sedation)

-EKG abnormalities/arrhythmias (high doses)

-orthostatic HTN

are TCAs quickly or slowly absorbed?

slowly

-patients can drive to ED if they think they've ingested a fatal dose

do TCAs interact with other drugs?

yes

-wide range of potential drug interactions

MAOIs (monoamine oxidase inhibitors) indications for use?

depression

-specifically refractory

-MAOIs MOA?

irreversible, nonselective inhibitors of monoamine oxidase enzyme, blocking the destruction of neurotransmitters (epinephrine, norepinephrine, serotonin, dopamine)

do MAOIs work quickly or slowly?

QUICKLY

-faster than SSRIs

-relief of sx in as soon as days up to 2 weeks

contraindications of MAOIs?

-drug interactions (especially with other sympathomimetics)

-concomitant use with SSRIs (serotonin syndrome risk)

-concomitant use with TCAs (serotonin syndrome risk)

-foods with tyramine (risk of hypertensive crisis)

side effects of MAOIs?

Common:

-insomnia

-reduction in REM sleep

-weight gain

-postural hypotension

-sexual disturbances

Serious:

-serotonin syndrome

-hypertensive crisis

why are tyramine rich foods avoided with MAOI use?

MAOIs block monoamine oxidase, which breaks down tyramine (stimulates norepinephrine release). additional supplementation then of tyramine with inhibition of breakdown results in increase in norepinephrine and hypertensive crisis.

trazodone (desyrel)

atypical antidepressant commonly used off label for insomnia

-strong sedative effects

mirtazapine (remeron)

tetracyclic antidepressant

mirtazapine MOA?

presynaptic alpha antagonist that increases synaptic norepinephrine and serotonin

-potent antihistamine blocking response

side effect of mirtazapine blocking antihistamine?

weight gain

mirtazapine indications?

depression

Where is Mirtazapine metabolized?

liver and kidneys

Lithium (lithobid/eskalith) indications of use?

-bipolar disorder (prophylaxis and treatment of manic phase)

-treatment of refractory depression (adjunct)

contraindications of lithium?

-renal disease

-cardiovascular disease

-severe dehydration/sodium depletion

concern about lithium?

narrow therapeutic index

where is lithium excreted from the body?

urine

what ages have decreased renal excretion of lithium? increased?

decreased: older patients

increased: younger patients

what needs monitored while on lithium?

-renal function (creatinine, BUN)

-lithium level (toxicity)

-TSH, T4 (risk of hypothyroidism with LT use)

serious side effects of lithium use?

-GI (N/V, diarrhea)

-renal failure

-neurological (ataxia, tremor, confusion, delirium, seizures)

side effects of lithium use?

cardio

-arrhythmia

-EKG changes

-hypotension

endocrine

-goiter

-hypothyroidism

nephrotoxicity

weight gain

Nausea/GI irritation

memory disturbances

what is unique about lithium?

lacks sedative, euphoriant, or depressive effects in individuals who do not suffer from psychiatric illness

does lithium have drug interactions?

yes, many

-ex: NSAIDs, diuretics, ACE inhibitors, fluoxetine (prozac)

first generation antipsychotic (FGAs) examples?

-chlorpromazine (thorazine)

-prochlorperazine (compazine)

FGAs indications for use?

-psychosis

-acute agitation/delirium, acute mania

-N/V

Rare:

-Tourette's syndrome

-intractable hiccups

therapeutic effects of FGAs come from where?

dopamine blockade

what other receptors are antagonized by FGAs?

-adreneric

-cholinergic

-histamine H1 receptors

half life of FGAs?

12-24 hours (once daily dosing)

-highly lipophilic

who might have impaired ability to metabolize antipsychotics?

elderly and very young

FGAs contraindication?

severe CNS depression

side effects of FGAs?

-dry mouth

-constipation

-difficulty urinating

-orthostatic hypotension

-ejaculatory failure

-sedation

-extrapyramidal syndrome

-tardive dyskinesia

-akathisia (restlessness, can't sit still)

-dystonia (muscle spasm of face, tongue, back, and neck)

rare but serious side effects of FGAs?

-neuroleptic malignant syndrome (NMS)

-agranulocytosis

-long QT interval

second generation atypical antipsychotic examples?

-olanzapine (zyprexa)

-risperidone (risperdal)

-quetiapine (seroquel)

indications for use of second gen. atypical antipsychotics?

-disorders of thought

-depression or mania with psychotic features

-bipolar disorder

-severe agitation and delusions in patients with dementia

contraindications for use of second gen. atypical antipsychotics?

history of neuroleptic malignant syndrome

MOA of second gen. atypical antipsychotics?

antagonize variety of receptors, primarily dopamine and serotonin (5-HT)

how are second gen. atypical antipsychotics eliminated?

hepatic metabolism

serious side effects of second gen. atypical antipsychotics?

-increased mortality in elderly

-endocrine (weight gain, exacerbation of diabetes, hyperglycemia, dyslipidemia, hyperprolactinemia)

-neuroleptic malignant syndrome

-extrapyramidal symptoms

common SEs of second gen atypical antipsychotics

-orthostatic hypotension

-sedation

-anticholinergic

-nausea and vomiting

examples of natural antidepressants

-exercise (increases endorphins)

-exposure to sunlight

-supplements (ex: St. John's wort, fish oil)