Your patient is a young woman that has feelings of sadness and hopelessness after her sister became ill. What may be the molecular causes of her depression?
inhibition of storage of amine neuotransmitters leads to depletion of amine neuotransmitters (serotonin, NE, dopamine) which induces depression
You presscribe fluoxetine to your pt that has symptoms of depression. How do fluoxetine and other antidepressants work?
- the overall immediate action is to increase amounts of serotonin and/or NE at the synapse
- MAOIs-- increase monoamines and leads to increased release of neuotransmitters
- TCAs and heterocyclic--inhibit the NE and 5-HT (serotonin) transporters--increasing serotonin and NE
- SSRIs--inhibit 5HT transporter to increase 5HT in the cleft
The patient that you prescribed fluoxetine is complaining that it does not work after 2 weeks of taking it. Why is there a delay in the onset of drug action?
- fluoxetine has a long half-life and its withdrawal effects are less
- the "amine hypothesis" to the development of depression does not explain why it takes weeks for these drugs to work because the biochemical effects of them occur immediately
- (this was pretty vague...but the best i got)
During your visit with your pt that is experiencing symptoms of depression you ask her specifically if she has had any thoughts about suicide. Why did you do this?
fluoxetine has been shown to increase risk of suicide in children and adults so it would be good to know if she has had any of these thoughts before prescribing it to her
You prescribed fluoxetine for your pt to treat her symptoms of depression. What should she be observed for in the future?
- increased suicide risk
- may impair blood glucose regulation in diabetics
- may induce a hyponatrmia and elevated urine osmolarity by causing inappropriate ADH secretion (SIADH)
- TCA+SSRI--may cause serum [TCA] to rise to toxic levels
- MAOI+SSRI-- dangerous interactions and serotonin syndrome (allow 14 days between the two)
- potentiate agents that are metabolized by CYP1A2 and other CYPs (carbamazepine, barbs, benzos, antipsychotics and antidepressants)
You prescribed fluoxetine (an SSRI) for your pt that has been experiencing symptoms of depression since her sister's illness. Why was a TCA or MAOI not prescribed?
- SSRIs are the current drug of choice to tx depression
- TCAs--have many adverse rxns such as blockade of AChR (blurred vision, dry mouth, urinary retention/constipation...), cardiac overstimulation, sedation, sexual dysfunction and weight gain
- MOAIs--produces acute hypertensive crisis with indirect acting sympathomimetics, severe headaches, and danger of intracranial bleeding