Exam 1 - Antidepressants Flashcards
Depression Treatment Key Takeaways:
Medications are only one part of treatment
R/O bipolar disorders prior to initiating antidepressants
Certain medications may work for some people and not for others
Macro level data does not show superiority of any agent
Greater depressive sx predicts greater response to medication, in general
Side effects can often be troubling
Adherence issues are common
Treatment with more than one antidepressant or treatment with one antidepressant and one additional agent for augmentation is often reasonable
Major Depressive Disorder
SIG-E-CAPS:
Sleep changes
Interest (loss of)
Guilt
Energy (lack of)
Cognition/concentration
Appetite
Psychomotor
Suicide/death thoughts** (high risk of this in depression, always assess)
Treating Depression
Mild Depression: Non-pharmacologic interventions (e.g. CBT, guided self help, interpersonal psychotherapy and other lifestyle and psychosocial interventions.
Severe-chronic depression: Consider antidepressant
Depression w/ psychotic features: Antipsychotic and an antidepressant or ECT.
Factors that impact antidepressant selection
Previous patient or family member response to antidepressants (if any)
Impact on psychiatric or medical comorbidities
Clinician familiarity
Patient preference
Safety in overdose
Availability
Cost
Drug to drug interaction
Top distressing side effects: Sexual dysfunctions, sleep disturbance, weight gain
Theories of Depression: Monoamines
Monoamine hypothesis
Deficit of monoamines (serotonin, norepinephrine, dopamine)
Delayed onset of therapeutic response to antidepressants (2 to 6 weeks)
Changes in receptors takes time
Problems with the monoamine hypothesis
Theories of Depression: Neurogenic
Neurogenic theory
Neurons become damaged, a neurodegenerative process
Genetic vulnerability + stress = disorder
Medication, therapy, etc. can Increases BDNF (brain-derived neurotrophic factor) “fertilizer for the brain cells” to help repair neurons and connections
BDNF can be increased via medication, therapy, or other interventions (exercise) to some extent
Neurotransmitters/Monoamine Hypothesis
Depression=↓Serotonin; ↓Dopamine; ↓NE
Monoamine Hypothesis: Deficient brain 5HT and/or NE results in depression
Antidepressants
Etiology:
Dysregulation in 1 or more biogenic amines (i.e. 5HT, NE, DA)
Low level precursor tryptophan
Target Symptoms: Depressed mood, sleep/rest distress, anxiety, irritability, impaired concentration/memory, appetite disturbances, agitation, anhedonia, impaired energy/motivation.
Classes: SSRI, SNRI, NDRI, SPARI, TCA, MAOI
Antidepressants
General Information:
All antidepressants have similar response rates but differ in safety and side effect profiles.
60-70% of patient with MDD will respond to antidepressant meds.
Most antidepressants require a trial of at least 3-4 weeks for effect and in some cases 6-8 weeks for noticeable effects.
Maintenance therapy: 6-13 months
Most antidepressants have a withdrawal phenomenon= Educate patients not to stop abruptly
Dizziness, headaches, nausea, insomnia, anxiety, electric-like shocks “zaps”, malaise
Depends on dose and half-life
Antidepressants
Factors affecting drug choice= Cost, patient symptoms, previous treatment of patient or family member, side effect profile, comorbid conditions, risk of suicide
Side Effects: Sexual dysfunction (25-30%), GI (nausea/diarrhea)-Give w/ food, insomnia, headaches, anorexia/weight loss, Akathisia
Lab Monitoring: TSH, CBC, Chemistry, Folate and vitamin B12 , UA
STAR-D Study Implications
The longer a person goes without responding to treatment, the less likely response becomes overall
Switching medications to a different class or to a different SSRI is a reasonable strategy but provides only modest improvement for most
On a macro level, any antidepressant is just as likely to be effective as any other antidepressant
Individual responses can be hard to predict
High relapse rates for chronic depression
More complex individuals have more difficulty with response/remission (e.g. other psychosocial stressors, medical issues, etc.)
The Major Categories
SSRIs – commonly used d/t safety and tolerability
SNRIs
Heterocyclic antidepressants (i.e. TCAs and tetracyclic)
MOAI
Atypical/Miscellaneous antidepressants
Selective Serotonin Reuptake Inhibitors (SSRIs)
Mechanism of Action:
Inhibit presynaptic serotonin reuptake pumps = ↑ availability of 5HT in synaptic clefts.
Cause downstream effects increasing brain plasticity – explains the delay of antidepressant effect.
1st line
Most prescribed class d/t
Low incidence of side effects – most resolve with time
No food restrictions
- Safer in overdose
Better tolerated
May initially worsen anxiety or panic attacks
Selective Serotonin Reuptake Inhibitors (SSRIs)
Low incidence of side effects
Transient (lasting 1-2 weeks especially GI)
Side Effects: Sexual dysfunction (30-40%)- decreased libido, anorgasmia, delayed ejaculation – occurs weeks to months (typically do not resolve)
GI (nausea/diarrhea)-Give w/ food, insomnia, headaches, anorexia/weight loss, Akathisia, sedation, agitation, Hyponatremia / SIADH, decreased platelet aggregation-risk for bleeding and bruising
Seizures- rare
BLACKBOX WARNING: Increased suicidality in children, adolescents and young adults
NOTE: Remember FFPECS
Common result of blocking serotonin reuptake is enhancement of postsynaptic serotonin activity at all serotonin receptors in the brain
5-HT1 = antidepressant and anxiolytic
5-HT2 and 5-HT3 = adverse effects
5-HT2 = insomnia, anxiety, agitation, and sexual dysfunction
5-HT3 = nausea
The SSRIs
Fluoxetine(Prozac) 20-80mg
Longest half –life =2-3 days(no need to taper)
Safe in pregnancy
Approved in use of Child/Adolescent
Approved for Buliemia
Can be dosed 1x/wk
Can elevate levels of antipsychotics – watch for increased side effects
Consider in patients w/ poor adherence d/t long half life
Activating” or energizing effect (Stahl, 2013)
Combination with olanzapine for psychotic depression
The SSRIs
Fluvoxamine(Luvox) 50-300mg
FDA approved for OCD
Common S/E: Nausea, vomiting
The SSRIs
Paroxetine (Paxil) 20-50mg
Considered “dirty” -
Potent CYP26 Inhibitor = several drug to drug interactions
Common side effects – Anticholinergic and sexual dysfunction
Short half-life = withdrawal phenomenon
Fairly significant side effects including sexual s/e
“Paxil packs on the pounds”
Can be sedating, take around dinner time
The SSRIs
Escitalopram (Lexapro) 10-20mg
Levo-enantiomer of citalopram, similar efficacy
Dose dependent QTc prolongation
Fewer drug –drug interactions.
The SSRIs
Citalopram (Celexa)
20-40mg
Associated with dose dependent QTC prolongation in doses 40+mg
Max dose in Geriatrics= 20mg.
Fewer drug interactions
Most Lethal in OD
The SSRIs
Sertraline(Zoloft) 50-200mg
Has the most GI side effects
Very few drug interactions
Give with food
Activating (Agitation, anxiety)
Favored during pregnancy and nursing (MCPAP for Moms, 2014)
Activating Antidepressants – good for patients who want to avoid medications that cause tiredness – e.g. Fluoxetine
Advantage of SSRIs over other classes of meds
When choosing an SSRI= Consider the inhibition of CYP-450 isoenzymes (induction vs. inhibition) – be familiar with these concepts
Most lethal SSRI in overdose ? (Citalopram) consider cardiac effects
Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)
Consider w/ patients who have significant fatigue or comorbid chronic pain
Mechanism of Action: Inhibits dual reuptake of NE and 5HT = ↑ extracellular concentrations of NE and 5HT
Side Effects: Sustained elevation in BP Nausea, diarrhea, dizziness, anticholinergic
All SNRI can increase blood pressure, cause tremor (beta receptor stimulation)
Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)-
Venlafaxine (Effexor ) 75-375mg BID
MDD, GAD, neuropathic pain
Useful in treating anxiety and panic attacks in depressed patients
XR available
New form Desvenlafaxine (Prestiq)= expensive
Short half life
Very hard to taper and d/c
Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)-
Duloxetine (Cymbalta) 40-120mg/day
Can increase LFTs
Used for depression, neuropathic pain and in fibromyalgia
Hepatotoxicity (monitor LFTs)
Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)-
Levomilnacipran(Fetzima)
20-120mg /day
Associated w/ more side effects (HTN, decrease appetite, Palpitations, diaphoresis etc.)
Norepinephrine- Dopamine Reuptake Inhibitor (NDRIs)
Mechanism of Action: Inhibits reuptake of NE and DA
Side Effects: Headache, tremors, tachycardia, insomnia, anxiety, decreased appetite
Most helpful for target sx of low energy, anhedonia, low concentration, or if having sexual s/e from SSRI