Antidepressants Flashcards
Serotonin Synthesis
- Tryptophan
- 5 - Hydroxytryptophan
- 5 - Hydroxytryptamine
4 Classes of antidepressants
- MAO inhibitors
- Tricyclic Antidepressants
- SSRI
- SNRI
How do MAO inhibitors work
- MAO destroys NE reuptake
- If the NE reuptake is inhibited, more NE will be available
Examples of MAO inhibitors
- phenelzine
- pargyline
Adverse effects of MAO inhibitors
- Hypertensive crisis - inhibited MAO cannot eliminate the excessive levels of NE
- Interactions with any other NE elevating sympathomimetics - hypertension
- interaction with meperidine can produce malignant hyperthermia
Reversible MAOa (destroys serotonin and NE) inhibitor
Moclobemide
- Decreases risk of toxic adverse effects associated with tyramine by releasing MAO from inhibition if NE levels are too high
MAOb (destroys dopamine) Inhibitors
Selegiline
- aim to increase Dopamine levels and are used to treat Parkinson’s
Tricyclic Antidepressants
Work by inhibiting presynaptic reuptake of serotonin, norepinephrine and dopamine - increasing levels of serotonin and dopamine
Examples of Tricyclic Antidepressants
Amitriptyline
Imipramine
Adverse effects of Tricyclic antidepressants
- Anti-histaminicn (fatigue and weight gain)
- Anti - Muscarinic (constipation, blurred vision, dry mouth, fatigue)
- Anti Adrenergic (Anti alpha 1 effect: hypotension and dizziness)
- Decreased libido
SSRI - Selective Serotonin Reuptake Inhibitors
Increase levels o serotonin in the synapse
Examples of SSRIs
Fluoxetine (prozac)
Citalopram (celexa)
Escitalopram (cipralex)
Paroxetine (Paxil)
Sertraline (zoloft)
Adverse effects of SSRIs
- Anorexia
- Insomnia
- Sexual Dysfunction (relating to ejaculation or orgasam and decreased sexual drive)
- Anxiety
Serotonin Syndrome
- Can occur with any drug or combination of drugs that increase serotonin levels
- Hyperreflexia and tremor in lower limbs
- Increased bowel sounds
- Hypertension
- Agitation
- Diaphoresis
- Mydriasis
- Delirium
- Muscular rigidity
SHIVERS mnemonic
S - Shivering
H - Hyperflexia
I - Increased body temp
V - Vital Sign Instability
E - Encephalopathy (ALC)
R - Restlessness
S - Sweating
5 HT + NE Reuptake Inhibitors Examples
- Venlafaxine (effexor)
- Duloxetine (Cymbalta)
- Desvenlafaxine (Pristiq)
Advantages of 5 HT and NE Reuptake Inhibitors
- Increased levels of 5 HT and NE
- Mechanism of action resembling tricyclic antidepressants
- Tend to have a faster therapeutic effect
Adverse Effects of 5 HT and NE Reuptake Inhibitors
- Nausea
- Anorexia
- Agitation
- Problems with ejaculation
- Anorgarsmia
NE + DA Reuptake Inhibitors Example
Bupropion
- Wellbutrin, Zyban
Uses for NE + DA Reuptake Inhibitors
- Useful to reduce cravings in people trying to quit smoking
- Also used as an anti depressants
Adverse Effects of NE + DA Reuptake Inhibitors
- Sympathetic stimulation (Headache, tachycardia, tremors, agitation, suppressed appetite)
- Sleep disruption
- Dry mouth
Alternative treatments for depression
- repetitive Transcranial Magnetic Stimulation (rTMS)
- Electroconvulsive therapy (ECT)
treatment for bipolar disorder
- Lithium
Adverse effects of Lithium
- Nausea
- Thirst
- Frequent Urination
- Fine tremors
- at high doses - seizures
2 classes of Antipsychotics
Typical
Atypical
Typical Antipsychotics
- Chlorpromazine
- Haloperidol
Positive Symptoms of Psychosis
-Auditory and visual hallucinations
- inappropriate gestures
- repetition of movement
- strange language
- pressure of speech
- disorganized behaviour
- agitation
