Chapter 5 Tricyclic and Heterocyclic Antidepressants
OVERVIEW
Chemotherapy of Depression
1. Severity and duration of depression are the major indicators of the necessity for pharmacotherapy.
2. Depression results from disorder of neurotransmission.
3. Antidepressants prescribed in adequate doses correct abnormal neurotransmission.
4. Choice of antidepressants (do not require blood level monitoring).
5. Neuotransmitter Action (major/minor reuptake inhibition):
S = serotonin; N = norepinephrine.
High-Sedating
Amitriptyline (S/N)
Doxepin (S/N)
Maprotiline (N)
Trazodone (S)
Trimipramine (S/N)
Low-Sedating
Desipramine (N)
Amoxapine (N/S)
Imipramine (S/N)
Fluoxetine (S)
High -Anticholinergic
Amitriptyline (S/N)
Imipramine (S/N)
Trimipramine (S/N)
Low-Anticitolinergic
Desipramine (N)
Fluoxetine (S)
Amoxapine (N/S)
Maprotiline (N)
Trazodone (S)
6. Nortriptyline has “therapeutic window”; requires blood level monitoring; may produce less postural hypotension.
7. Amoxapine has rapid onset of action and weak neuroleptic effect.
8. In psychotic depression start high-potency neuroleptic first, then add antidepressant.
9. Cyclic antidepressant side effects include: drowsiness. dry mouth, constipation,tremor, speech blockage, sexual dysfunction, increased sweating, postural hypotension. tachycardia. and cardiac arrhythmias.
10. Therapy should continue for at least 4 months after complete recovery from depression, then taper dose gradually; should never be abruptly discontinued.
11. If patient fails to respond, consider the following:
Dosage adjustment.
Trial of drug that acts on alternative neurotransmitter.
Addition of triiodothyronine, lithium, carbamazepine. or low dose of neuroleptic.
Trial of MAOI alone or in combination with tricyclic.
If patient is suicidal and does not respond to an initial adequate
medication trial, consider a course of electroconvulsive therapy.