Dr. Ron’s Research Review – April 25, 2018

©

This week’s research review focuses on inositol and lithium-induced psoriasis.

Inositol

Fifteen patients with psoriasis, who were taking lithium, took part in a randomized, double-blind, placebo-controlled, crossover clinical trial comparing the effect of inositol supplements with those of a placebo (lactose). Changes in the severity of their psoriasis were measured by Psoriasis Area and Severity Index scores recorded before and after the different courses of treatment.
The effect of inositol supplements on the psoriasis of 11 patients who were not taking lithium was evaluated in the same way.  The inositol supplements had a significantly beneficial effect on the psoriasis of patients taking lithium. No such effect was detected on the psoriasis of patients not on lithium.  The use of inositol supplements is worth considering for patients with intractable psoriasis who need to continue to take lithium for bipolar affective disorders. (Allan et al., 2004)

The “inositol depletion hypothesis” has been put forward to explain the effect of lithium on manic- depressive psychosis. Inositol is a constituent of the intracellular phosphatidyl inositol second messenger system, which is linked to various neurotransmitter receptors, and brain inositol levels fall as lithium inhibits the action of inositol monophosphatase. Inositol levels in other tissues also fall after lithium treatment. As inositol, if taken in low doses, passes poorly through the blood–brain barrier, treatment with it might be expected to help peripheral side-effects without significantly hindering any beneficial central action. Indeed, inositol has already been used successfully in this way to antagonize some of these peripheral side-effects, such as polyuria, without altering the control of the bipolar affective disorder.

Dr. Ron


 

Articles

The effect of inositol supplements on the psoriasis of patients taking lithium: a randomized, placebo-controlled trial.
            (Allan et al., 2004) Download
BACKGROUND:  Lithium carbonate is the most widely used long-term treatment for bipolar affective disorders, but its ability to trigger and exacerbate psoriasis can become a major problem in patients for whom lithium is the only treatment option. Inositol depletion underlies the action of lithium in bipolar affective disorders and there are good theoretical reasons why the use of inositol supplements might be expected to help this group of patients. OBJECTIVES:  To determine whether inositol supplements improve the psoriasis of patients on lithium therapy. METHODS:  Fifteen patients with psoriasis, who were taking lithium, took part in a randomized, double-blind, placebo-controlled, crossover clinical trial comparing the effect of inositol supplements with those of a placebo (lactose). Changes in the severity of their psoriasis were measured by Psoriasis Area and Severity Index scores recorded before and after the different courses of treatment. The effect of inositol supplements on the psoriasis of 11 patients who were not taking lithium was evaluated in the same way. RESULTS:  The inositol supplements had a significantly beneficial effect on the psoriasis of patients taking lithium. No such effect was detected on the psoriasis of patients not on lithium. CONCLUSIONS:  The use of inositol supplements is worth considering for patients with intractable psoriasis who need to continue to take lithium for bipolar affective disorders.

 

References

Allan, SJ, et al. (2004), ‘The effect of inositol supplements on the psoriasis of patients taking lithium: a randomized, placebo-controlled trial.’, Br J Dermatol, 150 (5), 966-69. PubMed: 15149510