where people feel lightheaded when they move from a sitting position to a standing position.
You can also have alpha 2 antagonism.
They will complain of dizziness and also a reflex tachycardia so their heart rate climbs when they stand up.
Now the older drugs have more side effects than newer drugs have fewer side effects.
So when you take a look at the drugs on this spectrum
here you can see that amitriptyline is the oldest of the drugs first used in the 1960s,
and the newer drugs like desipramine have fewer side effects.
The norepinephrine uptake inhibition can cause dry mouth, urinary retention, and tremor.
The reuptake of serotonin can cause GI disturbances and the antagonism of serotonin can cause nausea.
One of the big concerns that I always have with tricyclic antidepressants
is that your seizure threshold is reduced so patients
are going to have an increase rate of seizure that is also seen in the monoamine oxidase inhibitors.
There's an additive effect with alcohol or ethanol.
Depressive patients are at high risk for ethanol abuse so TCAs
become particularly problematic in those group of patients.
The other issue that we have to be very aware of with TCAs
is that they may antagonize methyldopa and clonidine,
so patients who are taking these drugs, methyldopa or clonidine,
whether it's for blood pressure or for postmenopausal symptoms
can have a significant interaction between the two sets of drugs.
Now there are three Cs of TCA toxicity -- coma, convulsions, and cardio toxicity.
So if you remember these about the TCAs, the three Cs are very, very important.