Which of the following is classified as a secondary amine?
Antidepressants (tricyclic)
Tricyclic antidepressants (TCAs) are used less commonly now for depression due to their side-effects and toxicity in overdose. They are however used widely in the treatment of neuropathic pain, where smaller doses are typically required.
The tricyclic antidepressants can be divided into first generation tricyclics (tertiary amines), and second generation tricyclics (secondary amines).
The secondary amines are said to have a lower side effect profile and to act primarily on noradrenaline. The tertiary amines are thought to boost serotonin and noradrenaline.
Secondary amines include:-
- Desipramine
- Nortriptyline
- Protriptyline
- Amoxapine
Tertiary amines include:-
- Amitriptyline
- Lofepramine
- Imipramine
- Clomipramine
- Dosulepin (Dothiepin)
- Doxepin
- Trimipramine
- Butriptyline
Common side-effects of TCAs include:-
- drowsiness
- dry mouth
- blurred vision
- constipation
- urinary retention
Choice of tricyclic
- low-dose amitriptyline is commonly used in the management of neuropathic pain and the prophylaxis of headache (both tension and migraine)
- lofepramine has a lower incidence of toxicity in overdose
- amitriptyline and dosulepin (dothiepin) are considered the most dangerous in overdose
