Exam 3 - Behavioral Medicine Flashcards
MAJOR DEPRESSIVE DISORDER
…
Pharmacotherapy
Older agents are less specific and have a smaller therapeutic index. Ex: TCA.
2-3 fold OD = fatal.
Newer agents are more specific and have a wider therapeutic index. Ex: SSRIs.
Multiple fold OD = OK.
Placebo
Placebo effect takes place with anti-depressant medications, makes it difficult to determine if therapy is effective.
Trials confounded with placebo affect, some trials have poorly defined outcomes.
Depression, can be secondary to:
- Hypothyroidism
- Parkinson’s disease
- Inflammatory conditions
What medications can cause depression?
Beta Blockers
Levetireacetam (Keppra)
Isotretinoin
Topiramate (Topamax)
Clonidine
Corticosteroids
OC
Methyldopa
Interferons (Ribovirin)
Tamoxifen
Anxiety
- GAD, OCD, Panic disorder, PTSD, Phobias
- Can inhibit normal function; often associated with depression.
Why do people get depressed?
- Due to depressed levels of monoamines (serotonin, NE).
- Experience depression due to deficiency of catelcholamines.
-Meds address the issue to supplement the catelcholamines.
Reserpine
Antihypertensive; causes synapses to kick out catelcholamines, so they get metabolized.
Causes a deficiency of NE, epi. In addition to hypotension/bradycardia from drug, you’d see depression develop in patients.
If you give drugs to increase serotonin and fix deficiency, you should see “immediate” effect on depression.
Why don’t the drugs work immediately?
Therapeutic effect of drugs take weeks to become effective; can be 4-6 weeks.
A lot of pts D/C therapy early, so need to let them know therapeutic effect takes a while.
Mechanism of depression
- Downstream effects:
- Receptor expression
- Gene transcription
- No final theory how antidepressants work; just know they work
Three phases of treatment
Acute phase
Continuation phase
Maintenance phase
Often requires lifetime therapy.
Especially for recurrent symptoms.
Situational based - can get away with short-term therapy
Acute phase
First 6-12 weeks of treatment
- Remission of symptoms
- Important to educate patients on increased risk of SUICIDE during this time.
Continuation phase
4-9 months into treatment:
-Eliminate residual symptoms to prevent recurrence.
Maintenance phase
12-36 months into treatment:
-Prevent recurrence.
Non-pharmacologic therapy
Psychotherapy
-Affects are additive with antidepressants
ECT
Repetitive transcranial magnet stimulation (TMS)
PHARMACOLOGICAL THERAPY
..
How do you know what antidepressants to give?
Can’t predict which agent a patient will respond to.
Choice made empirically:
- history of response
- concurrent medical illness
- presenting symptoms
- cost
- drug to drug interactions
- ADR profile
- Patient preference
Escitalopram (Lexapro)
Causes anorgasmia
Antidepressants
How long does it take to reach therapeutic effects?
- 2 to 6 weeks for therapeutic effects
- Adverse effects occur within hours to days
- 20-30% failure rate with antidepressants
Failure Rate
- Intrinsic resistance to therapy
- Due to inadequate dosage or duration
- Noncompliance
- ADR or delay in therapy
Placebo effect efficacy/recurrence
- 30-40% efficacy
- Natural remission in 6-12 months
- 50-70% experience recurrence
TCA vs. SSRI
- Same efficacy
- Differ in ADR profiles
- Therapeutic doses and overdose
MAOI (monoamine oxidase inhibitors)
- Oldest class
- Non-specific MAOI A + B inhibitors
- Prevent breakdown of catecholamines 5HT and NE
- Prevent breakdown of NT; get more NT in synapse
TCA (tricyclic antidepressants)
- Inhibit reuptake of 5HT and NE
- More NT in synapse
SSRI (Selective serotonin reuptake inhibitors)
Specifically inhibit reuptake of 5HT to leave in synapse
SNRI (Selective serotonin and NE reuptake inhibitors)
- Inhibit reuptake of NE and 5HT
- Have a balance
What drug activates alpha-2 agonists and treats HTN?
Clonidine
- acts as alpha-2 receptor agonist
- decreases NE release
In general, MOA antidepressants:
-Enhance NE and 5HT effects, MOA not fully known
Long term therapy leads to adaptive and regulatory changes:
- increased SE and NE receptor density
- Increased 2nd messenger signaling via G proteins
- Increased expressoin downstream of gene products
MAOIs - Name them, MOA, and main risk with taking them.
SPIIT
- Iproniazid - first agent
- Phenelzine (Nardil) - MC
- Isocarboxazid
- Tranylcypromine (Parnate) - MC
- Selegiline transdermal (Emsam)
MOA: Irreversible inhibitor of MAO-A and MAO-B. Affects metabolism of 5HT, NE, and DA (dopamine).
Affect exogenous monoamines (tyramine).
-If you inhibit breakdown of NT, plus more NT being produced, and tyramine from diet = at risk for serotonin toxicity.
Iproniazid
Iproniazid
- MAOI
- Originally antituberculosis
- Elevated mood in treated patients, so they started using it for depression.
ADR MAOIs
- Postural hypotension (most common)
- Weight gain
- Decreased libido
- Anorgasmia
- HYPERTENSIVE CRISIS
How do MAOI cause postural hypotension?
-Postural hypotension
Older patients with less cardiovascular reserve - when they go from sitting to standing, their vessels don’t vasoconstrict, because there’s no release of NE/epi.
-If you have a higher set point of NE, bc its not degraded, you cant release extra amount to cause the vasoconstriction. Can’t adapt to the change in pressure.
What S/S are consistent with hypertensive crisis?
How do MAOI cause hypertensive crisis?
- N/V and HA
- Stiff neck
- Diaphoresis
- Looks likemeningitis, but BP: 200/110
- Risk of CVA and hemorrhagic stroke
MAOI on top of something else increasing catelcholamine levels:
- MAOI + SSRI/SNRI
- MAOI + Tyramine intake
Increase catelcholamine levels and cause hypertensive crisis.
Important education point on MAOI risk:
MAOI = irreversible inhibitors
- Because they’re irreversible inhibitors, the drug sticks around for 2 weeks.
- Wait the “2 week washout period” before starting a new drug!!!
- Still at risk for CVA and death after drug is discontinued
- Takes 2 weeks to regenerate enzymes
How do you treat hypertensive crisis?
Antihypertensives
- IV ACE inhibitors
- IV beta blockers
Drop BP until they get through wash out period and start metabolizing the catelcholamines again.
What are dietary restrictions on patients taking MAOI? Why?
NO TYRAMINE or it will increase production of catelcholamines.
Aged cheese Sour cream Yogurt Cottage cheese Wine / Beer Aged and processed meats MSG Fava beans Soy sauce Coffee Sauerkraut Licorice
Do not consume with MAOIs!
So many food interactions, run into issues with compliance that lead to toxicity.
What drugs have similar affects (to increasing tyramine intake) when taken with MAOIs?
Medications that will increase catelcholamines in the synapse:
- Amphetamines in ADHD
- Appetite suppressants
- Asthma meds
- Cocaine
- Decongestants (pseudoephedrine)
- Robitussin
Tricyclic antidepressants (TCAs)
AACDDIN
Amoxapine (Asendin) Amitriptyline (Elavil)* Clomipramine (Anafranil) Desipramine (Norpramin)* Doxepin (Sinequan)* Imipramine (Tofranil) Nortriptyline (Pamelor)*
- Derived from phenothiazines (antipsychotics)
- Not as specific as SSRI
- MOA: Inhibit the reuptake for 5HT and NE.
- Used to be first-line therapy for depression, now replaced with SSRIs (due to toxicity profile).
- Also used to treat insomnia and neuropathic pain.
What phenothiazine is used as an anti-emetic?
-Promethazine (Phenergan)
- Used as anti-emetics, like Reglan, because they’re dopamine antagonists.
- Blocking dopamine helps with N/V on chemoreceptor trigger zone.
When prescribing was limited, what could be prescribed for sleep that wasn’t a controlled substance?
- TCAs
- Trazadone
What TCA treats neuropathic pain of fibromyalgia?
Amitriptylene
What TCA treats nocturnal aneuresis?
Imipramine (Tofranil)
- Treats nocturnal aneuresis (bed wetting)
- Anticholinergic side effects - “dry as a bone”
ADR of TCAs -
- Sedating drugs at normal doses. Used for sleep. BUT HIGH doses, cause agitation and seizures.
- Midriasis (dilation)
- Hyperthermia in high doses
- Urinary retention
- Dry mouth/skin
- Decreased bowel motility
- Red is cutaneous vasodilation
- HR increases.
-Cardiac conduction delays - Na channel blocker, causes conduction delays that lead to arrythmias!!!
- Block alpha receptors, leads to orthostatic hypotension.
- Sexual dysfunction due to affected penile blood flow
- Weight gain
- Sedation
Used for neuropathic pain and sleep, mostly.
Safer antidepressants can be used.
Why is there an increase in suicide during the acute phase?
- Avolition: normally can’t act on SI thoughts, but now they have more energy to act on thoughts of self-harm.
- Higher burst of energy
SSRIs
CEFFPS
Citalopram (Celexa) Escitalopram (Lexapro) Fluoxetine (Prozac, Sarafem) Fluvoxamine (Luvox) Paroxetine (Paxil) Sertraline (Zoloft)
- Safer alternative to TCAs, because they ONLY work on serotonin receptors.
- TCAs work against Na channels, alpha receptors, muscarinic receptors.
- MOA: prevent reuptake of 5HT increasing the synaptic concentration. Selective for 5HT transporter.
- First-line for major depressive disorder.
- Patients can take 10 to 30-fold overdose without being fatal.
What is the relationship between Citalopram (Celexa) and Escitalopram (Lexapro)?
TEST QUESTION
They’re enantiomers.
Conversion of dose:
-Escitalopram => Citalopram
-10mg E = 20mg C
If on 20mg of Citalopram, switch them to 10mg Escitalopram.
- Every dose of Citalopram is double the dose of Escitalopram.
- Citalopram 40mg = 20mg Escitalopram
- Racemic mixture: Citalopram (50% of it is escitalopram).
Fluoxetine (Prozac, Sarafem)
-Fem?
Sarafem
- Treats premenstrual disorder
- fem = female
ADR SSRI
-Less ADR than TCAs, because they have a low affinity for alpha, histamine, and muscarinic receptors = fewer SE, better tolerated :)
- Less weight gain
- GI upset
- Sexual dysfunction
- HA
- Insomnia
What can result from abrupt SSRI discontinuation?
Abrupt D/C leads to withdrawal:
- Sleep disturbance
- Rebound anxiety and depression
- Taper them off dose slowly!!
- Does NOT occur as frequent in agents with longer half-lives or metabolites (fluoxetine).
If you’re tapering a patient off of an SSRI, but they start experiencing sleep disturbance, anxiety, or depression; what do you do?
If they have SE when coming off of the drug, you need to increase the dose and restart the titration.
If you’re worried about patient compliance when using an SSRI and tapering off, which drug is preferred?
Fluoxetine
- Longer half-life
- Active metabolite so you have a better taper in affect rather than an abrupt discontinuation.
What SSRI causes QT interval prolongation?
- Citalopram
- Escitalopram
What is the black box warning associated with SSRIs?
Increased risk of suicidality in children, adolescents, and young adults.
- Acute phase of treatment
- Applies to SSRIs, SNRIs, misc.
What are the possible mechanisms of suicide increase in SSRIs?
- Increased energy (akathisia) acutely leads to depressed patients acting on their suicidal thoughts.
- May lead to manic episode in bipolar patients.
SNRIs
Venlafaxine (Effexor) Desvenlafaxine (Pristiq) Duloxetine (Cymbalta) Milnacipran (Savella) Levomilnacipran (Fetzima)
- MOA: Non-tricyclic antidepressants, which target SERT and NET transporters. Prevent uptake of serotonin/NE.
- Fewer SE than TCAs.
- Other indications: fibromyalgia, peripheral neuropathies.
What SNRIs are used for neuropathic pain?
Duloxetine (Cymbalta)
What is the relationship between Venlafaxine (Effexor) and Desvenlafaxine (Pristiq)?
Enantiomers
SNRI ADR
- Nausea, GI disturbances (higher than SSRI).
- Sexual dysfunction.
What SNRI causes increases in systolic BP?
Venlafaxine
- Dose related increases in systolic BP.
- Happens because you block the reuptake of NE.
- Not good for HTN pts; do SSRI instead.
What SNRI causes nausea, dry mouth, constipation, insomnia, diaphoresis?
Duloxetine (Cymbalta)
Nausea, dry mouth, constipation, insomnia, diaphoresis.
Mixed Serotonergic Agents
- Trazodone
- Nefazodone
- Vilazodone (Viibryd) (new)
- MOA: 5-HT2 antagonists and 5-HT reuptake inhibitors (block serotonin reuptake and receptor).
- ADR: hypotension, dizziness, SEDATION.
Often prescribed for sleep if avoiding narcotics.
Trazodone (Desyrel) ADR
Trazodone (Desyrel)
- Blocks alpha 1 receptors, causes dizziness and hypotension (w/ reflex tach).
- Causes priapism!!
Why is Nefazodone (Serzone) used less frequently?
Nefazodone (Serzone)
-less use; cases of liver failure
Bupropion (Wellbutrin) MOA
Bupropion (Wellbutrin)
- MOA: Inhibits reuptake of NE and DA, so more is in the synapse.
- May enhance release of NE and DA as well to increase levels.
- Used for opioid addiction, overeating, use for weight loss.
- Also used for smoking cessation (Zyban).
How often do you take SR formulation and XL formulation of Bupropion (Wellbutrin)?
SR formulation = 2x daily
XL formulation = 1x daily
- Don’t mess up dosing - can halve it or double it.
- Leads to toxicity or increase in depressive symptoms.
If you have a patient on antidepressants who is having sexual dysfunction, what medication should you switch them to?
Buproprion
-Less sexual dysfunction than SSRIs.
Bupropion (Wellbutrin) ADR
- ADR: Nausea, vomiting, tremor, insomnia, dry mouth
- Agitation in some patients
-SEIZURES and ARRYTHMIAS – dose related; avoid in those who have a history of it!!!!
MISC ANTIDEPRESSANTS
…
Mirtazapine (Remeron)
- MOA: Antagonist at presynaptic alpha-2 receptors.
- Increases NE and serotonin release.
- Antagonizes 5-HT2 and 5-HT3 receptors.
- Antagonizes histamine receptors (see ADR).
- ADR: Somnolence, weight gain, dry mouth, constipation
Vortioxetine (Trintellix)
- Newer agent
- MOA: Acts as SSRI; 5HT agonist, partial agonist, and antagonist at various receptor subtypes.
- Affects 5HT3, 1A, 7, 1D, and 1B (don’t memorize this).
-CYP2D6 poor metabolizers may accumulate drug
- Switch over to if they have failed other therapies for depression.
- ADR: diarrhea, ejaculation dysfunction, nausea, orgasm dysfunction
If a patient is on Vortioxetine (Trintellix) and has an increase in side effects, what occurs?
-If they have poor CYP2D6 metabolism, the drug accumulates and causes more side effects.
What is Serotonin Syndrome?
Major effects:
- Altered mental status (seizures/agitation/comatose)
- Hyperthermia
- Autonomic instability (hypotensive/tachycardia).
- Increased muscle tone (clonus)
- R/O infection, amphetamine toxicity, etc.
S/S - sweating, hyperthermia, brady/tachycardia, hyper/hypotension, altered mental status/seizures, clonus, rhabdomyolysis.
When is a pt likely to experience Serotonin Syndrome?
-Can occur when taking multiple serotonergic medications at once (drugs that inhibit serotonin uptake)
- Mixing drugs from classes (TCA + SSRI).
- Including tyramine interactions (eating foods with tyramine).
- Seen most with MAOIs! Like Selegiline and Rasagiline.
If you have a patient diagnosed with major depressive disorder and a MRSA pneumonia, how do you treat?
Put them on Linezolid and make sure they’re NOT on any SSRIs.
-SSRI + Linezolid = increases risk of Serotonin Syndrome.
How do you treat serotonin syndrome?
Management
- Aggressive supportive care
- Hydration w/ IV fluids
- Evaporative cooling (when hyperthermic).
- Dantrolene - used to treat malignant hyperthermia.
- Cyproheptadine - has some serotonin-blocking effects to help.
Dantrolene
- Used to treat episodes of malignant hyperthermia.
- Peripheral muscle relaxer, so they’re less acidotic.
**Also used in NMS
Cyproheptadine
- 1st generation antihistamine
- Blocks effects of serotonin.
- Also used to stimulate appetite in muscle wasting syndrome.
Methylene Blue
Used for staining met hemoglobinemia.
When a patient is blue, but well-oxygenated, it can turn a blue patient pink.
Used as a dye for PTH glands to see where you need to resect, but acts as an MAOI. Pt getting PTH resection was on SSRI and not screened for interaction, pt started to get hyperthermic, muscles locked up, and had serotonin toxicity with it!!!
When would you want to use an agent with a long half-life or active metabolites?
Ex: Fluoxetine
- Good for patients with compliance issues
- May not need as long of a taper to prevent withdrawal, levels go down naturally.
- Be careful when adding on new medications.
If you had a pt on Fluoxetine for a while, but you wanted to discontinue it and start a new drug - What would you do?
Do not want to do it at the same time, because there will still be levels of fluoxetine (plus new drug).
Adding the new drug right away puts you at risk for serotonin toxicity.
Need to titrate down Fluoxetine. 1 week in, can start adding the new drug.
Chronic therapy leads to _____________.
Tissue accumulation; may lead effects to stay around longer.
What happens when you give antidepressants to a patient with cirrhosis?
Because these drugs are metabolized in the liver, the half-life may be extended in cirrhotic patients.
How do you therapeutically monitor these drugs?
- Drug levels don’t assess therapeutic efficacy.
- Drug dosage titration should be based on symptomatic response.
- Full effects may take up to 6 weeks
- Important patient education point!
After 6 weeks, if they had partial improvement:
May need to increase their dose.
After 6 weeks, if they had no improvement:
Switch to another agent.
If a patient fails one SSRI, like Citalopram:
It doesn’t mean they won’t respond to another agent.
Citalopram (Celexa) Escitalopram (Lexapro) Fluoxetine (Prozac, Sarafem) Fluvoxamine (Luvox) Paroxetine (Paxil) Sertraline (Zoloft)
Venlafaxine, Duloxetine, Buproprion (newer agents): drug interactions
Have fewer PK interactions.
SSRI: drug interactions
Have variable effects with CYP inhibition.
TCA: drug interactions
TCAs can be extensively metabolized by CYP enzymes.
- Usually metabolized by CYP2D6 and CYP3A4.
- Start low and titrate up.
CYP inhibitors will increase TCA levels ~ increased risk of toxicity.
What’s an important TCA reaction?
TCAs are highly protein bound.
-If a competitor drug comes and knocks TCA off of protein, it can increase free fraction of drug, therefore increasing TCA toxicity.
Any drug that affects serotonin can contribute to serotonin toxicity:
- Linezolid
- Methylene blue
- Triptans (Suma, Riza, Almo)
If your patient on an SSRI has a migraine, why is it bad to prescribe them -triptans?
Triptans
- Sumatriptan
- Rizatriptan
- Almotriptan
Triptans directly activate the serotonin receptors to vasoconstrict blood vessels. With further serotonin activation ~ would lead to further constriction, possible ischemia.
If you have an ICU patient with a history of MDD on an SSRI, but now they have a MRSA pneumonia, what can you do?
Do not have time to wait the “washout period” of 2-5 weeks like you normally would.
Stop SSRI and start Linezolid; need to treat them through the side effects.
If you kept them on SSRI during Linezolid treatment, they’re at a higher risk for serotonin toxicity.
What drugs cause QT interval prolongation?
For tx resistant depression, pts may be put on atypical antipsychotics with citalopram.
Putting them on both: increases risk for Torsades.
Sedative effect:
- Trazadone
- TCA
Synergistic effects with alcohol and benzodiazepines.
St. John’s Wort:
-Herbal supplement; used to treat mild to moderate depression.
- MOA: Hypericin in it works as MAOI, increases catelcholamine effects.
- At risk for serotonin toxicity when you use it with other antidepressants. Don’t want pts to take both.
- ADR: dry mouth, dizziness, confusion, allergic reactions
What are important drug interactions of St. John’s Wort?
- CYP3A4 and PGP inducer
- Inducing CYP3A4 metabolism will lower drug levels more quickly for those metabolized by CYP3A4.
Does FDA regulate supplements, like St. John’s Wort?
No; they have less oversight.
- Use a reputable brand
- Use same brand, to make sure you have the same amount of drug.
Oxycut is off the market for hepatotoxicity.