Poisoning in MRCP(1)

Poisoning in MRCP(1)-Lithium

For those who recently sat for thier Part 1, good luck to all of you and hope for the best!You can do it!
" There is always hope !"

My friend sat for his MRCP Part 1 in Singapore recently. He said that questions asked in MRCP are getting more difficult to answer now. I would like to talk about poisoning today. There are a few important subtopics you must remember when learn about common drugs which are asked in MRCP.

1) Common symptoms and signs when there is poisoning.
2) Possible antidotes.
3) Drugs interactions
4) Whether the drug can be cleared by dialysis ( very important fact to remember!)

Today, I am going to talk about Lithium. If I can still remember, this drug was asked in my MRCP Part 1 in 2003.

Introduction:

Lithium is used as mood stabilizer and can be used as a treatment for acute mania/hypomania. It has a narrow therapeutic range ( <1mmol).>Symptoms for toxicity (LITHIUM!!)

- Loose motion
-Impaired vision
-Tremor
-Hypothyroidism symptoms
-Increased thirst ( polydypsia)
-Urine output increased ( polyuria)
-Muscle weakness/metallic taste

Signs for toxicity

-hyper-reflexia
- ataxia/dysarthria
-Confusion/fits

Interactions

NSAID, Thiazide, Phenothiazide, pheytoin and methyldopa increase lithium toxicity

Treatment

No specific antidotes but dialysis may be indicated!