Antidepressants are most commonly used to treat depression, but also have a role in bipolar disorder, anxiety disorders, and other conditions. Start low, go slow, and don't give up too early. Up to eight weeks are necessary to observe a response.
Make sure patient is involved in this decision! Depression, without imminent suicidality, is not an emergency. Take time to plan treatments with the patient to maximize the chances of success.
use pictures to get messages across
TO DO: put up drawing of remission/relapse.
Cross-tapering is usually necessary when switching medications. There is little science to this, as long as you go relatively slowly.
TCAs have a narrow therapeutic window.
TCA overdose is rapidly absorbed, with a quick onset. CVS and CNS effects are seen in parallel, and coma in 24-48 hours. Sodium channel blockade is most dangerous effect. ECG can show SVT, with increased QRS >0.1 and right axis deviation.
Treat with best supportive care, charcoal, and sodium bicarbonate. Sodium will assist with restoring CV function. The drug has a large volume of distribution, with a higher concentrations of drug in tissue compared with blood, so it is not dialyzable.
TCAs inhibit NE, 5-HT, and sometimes DA re-uptake. Acting as muscarinic antagonists, they also have various anti-histamine effects.
The clinical effects of MAOIs last for 1-3 weeks after drug has disappeared from blood.
Hypertensive crisis and serotonin syndrome are the biggest risks.
Some cheeses, red wine, and fermented foods are high in tyramine. Blockade of liver MAO results in high blood levels of tyramine, which can cross the BBB and induce mass release of NE, resulting in hypertensive crisis.
MAOIs blocks major interneuronal degradative pathway for amine transmitters NE, DA, 5-HT irreversibly. This induces the accumulation and release of NTs.
Antidepressants all enhance the availability of selected neurotransmitters, leading to increased connectivity between and among neurons.
Immediately after taking a reutake inhibitor, autoreceptors lead to a drop in firing rate. Over time, however, cell firing increases over baseline.
Antidepresants also are protective against future episodes (NNT 4 for 1 year and 3 for 2 years) metaanalysis (Geddes et al, Lancet 2003)
Neurovegetative symptoms begin to change within 1-3 weeks, while the emotional and cognitive symptoms often take 2-6 weeks to begin changing. Accordingly, it is important to be particulary vigilant during the first few weeks, as patients may be at risk of suicide with their increased energy but persistent low mood.
Almost half of people have concerns about antidepressant addiction. Side effects are more common in elderly.
Common side effects include nausea, vomiting, sleep disturbance, and headache. If possible, encourage use for two weeks, as they are often transient. Sexual dysfunction can be very troubling for patients.
Antidepressants can have potentially fatal interactions, causing hypertensive crisis or serotonin syndrome. MAOIs are particularly worrisome regarding side effects.
Any antidepressant needs to be out of the system (5 half-lives) before going to MAOIs. When switching from a MAOI to another antidepressant, wait 2 weeks to allow irreversibly inhibited MAO to regenerate.
There is at least a theoretical risk of increased suicide ideation, allegedly with SSRIs, especially in young patients. This is a big legal risk, though with proper documentation and warnings to patients, it is very safe.
Some people will switch from depression to mania. This frequently occurs quickly and is more common in young patients. Stop treatment immediately.