BT_PO 1.55 Outline clinically important drug interactions with the autonomic nervous system

I love nature (and hate pesticides which is why those little critters were all over my roses). Go Ladybird! Go!

Well nothing like a small topic for the middle of the week.

I have been marking some practice MCQs for a registrar today and one of them was on antidepressants and clinically important interactions. Many of the current versions of these drugs have some effect on noradrenaline handling, which can cause issues in the peri-operative period, so I am going to keep my focus there for today (scope for plenty more posts on this LO…)

Evers and Maze Anaesthetic Pharmacology Ch 60 has a section on this topic and Hemmings and Egan (which has a new edition!) also has a good section in the Drugs for Neuropyschiatric disorders chapter.

Clinically important is the key phrase here – you should know the answer to all of these (although I have only included 4…)

BT_PO1.55 Outline clinically important drug interactions with the autonomic nervous system

Tricyclic antidepressants (TCA) increase sensitivity to indirect acting sympathomimetics T/F

Tricyclic antidepressants increase sensitivty to direct acting sympathomimetics T/F

The risk of central anticholinergic syndrome is increased in patients, given atropine, who are on concurrent TCAs T/F

Noradrenaline can be safely used in patients on older monoamine oxidase inhibitors (eg phenelzine) T/F

BT_PO 1.99 Lithium

The Hubble Space Telescope’s image of the star V838 Monocerotis 

On the way to work today I listened to a fascinating podcast about an Australian psychiatrist, John Cade, who discovered the benefit of using Lithium in the treatment of bipolar mood disorder. Apparently Lithium was one of the three elements created in the Big Bang along with H and He

Lithium is not a drug we encounter commonly in our anaesthetic practice, although it is still the gold standard treatment for severe bipolar mood disorder and has some interesting toxic effects. As such, I thought it was worthy of a post. None of this is particularly examinable, but still good to know.

Lithium is covered well in Katzung Basic and Clinical Pharmacology (Ch 29)

BT_PO 1.99 Outline the pharmacology of anti-depressant, anti- psychotic, anti-convulsant, anti-parkinsonian and anti- migraine medication

Lithium can mimic the actions of sodium in the generation of membrane potentials T/F

Lithium produces a nephrogenic diabetes insipidus which does not respond to vasopressin T/F

Patients on lithium often exhibit T wave flattening on their ECG T/F

Lithium is completely renally cleared T/F

Leukocytosis is almost universal in patients receiving lithium therapy T/F