May's comment

We have commented on more than one occasion that the antidepressant amitriptyline is still the gold standard for the treatment of neuropathic pain. This tricyclic antidepressant, as well as being a noradrenaline and serotonin reuptake inhibitor, has other pharmacological properties including the capacity to block acetylcholine receptors. This is the cause of some of its undesirable effects, such as urinary retention or a central mechanism of cognitive disorders like memory loss or the difficulty in recognising objects. This effect is particularly severe in people who are advanced in years. In this month's update, a group from the University of Augusta in the USA has performed some experiments on macaque monkeys and has compared the effect of amitriptyline and gabapentin, another neuropathic pain and anticonvulsant drug, on certain cognitive parameters. The authors show that taking amitriptyline can lead to cognitive disorders, something which does not occur with gabapentin. Gabapentin was even able to improve cognitive performance. The authors even suggest that this improvement can be linked with the neuropathic pain relief produced by this medication.

Prof. Juan Antonio Mico

Dr. Esther Berrocoso

May's question

Which of the following undesirable effects can most frequently be produced with amitriptyline, when used to treat neuropathic pain?:

1. Insomnia.

2. Cognitive disorders.

3. Psychomotor agitation.

4. Restless leg syndrome.

Answer to April's question

2. Duloxetine and venlafaxine are antidepressants with an analgesic action in neuropathic pain.