Table 3.

Studies on metformin administration in psoriasis patients.

Author	Year of Publication	Country	Type of Study	Metformin Therapy in Psoriasis	Dose
Brauchli et al. [42]	2008	Switzerland	Case-control	Effect of long-term use of metformin in obese patients associated with thiazolidinediones
Singh and Bhansali [45]	2016	India	Randomized	Metformin improved features of metabolic syndrome (MS). Metformin and pioglitazone improving MS parameters might account for the improved efficacy in psoriasis itself. The anti-proliferative and anti-inflammatory action of metformin might have resulted in improvement of the psoriasis. There is significant reduction in weight with the use of metformin, and due to controversy about increased risk of bladder cancer associated with pioglitazone, metformin can be preferred over pioglitazone in psoriasis patients with MS.	Metformin 1000 mg once daily (O.D) or pioglitazone 30 mg
Singh et al. [46]	2017	India	Randomized	Metformin has shown improvement in psoriasis and parameters of MS; hence, it can be used for the benefit of psoriasis patients having MS. The metformin group had greater percentage reduction in mean PASI, ESI, and PGA scores as compared with placebo. In total, 45% of the patients had complete improvement in MS in the metformin group as compared with 33.3% of patients in the placebo group. Patients taking metformin had statistically significant decreased weight, BMI, waist circumference, fasting plasma glucose, serum triglycerides, total cholesterol, and LDL-C as compared with patients taking placebo.
El-Gharabawy et al. [50]	2016	Saudi Arabia	Randomized Study	Metformin modulates the immune system (causing a significant decline in CD4+ T cells) in psoriasis and MS or impaired glucose tolerance and has a remarkable effect in the early stages of psoriasis. Therefore, either pioglitazone or metformin in combination with traditional anti-psoriatic drugs provides better results in the treatment of psoriasis than does either alone.	850 mg twice daily
Su et al. [51]	2019	Taiwan	Retrospective cohort study 1995–2014	Metformin can be prescribed for diabetic psoriasis patients without chronic kidney disease.