Comparison 1. Amlodipine versus control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Heart T2* (m/s) (change from baseline)	2		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.1 At 6 months	2	65	Mean Difference (IV, Random, 95% CI)	‐3.91 [‐9.65, 1.83]
1.2 At 12 months	2	74	Mean Difference (IV, Random, 95% CI)	‐0.27 [‐2.66, 2.11]
2 Myocardial iron concentration (MIC) (mg/g) (change from baseline)	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
2.1 At 6 months	2	65	Mean Difference (IV, Fixed, 95% CI)	‐0.23 [‐0.39, ‐0.07]
2.2 At 12 months	2	74	Mean Difference (IV, Fixed, 95% CI)	‐0.25 [‐0.44, ‐0.05]
3 Left ventricular ejection fraction (LVEF) % (change from baseline)	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
3.1 At 6 months	2	65	Mean Difference (IV, Fixed, 95% CI)	‐0.02 [‐2.49, 2.45]
3.2 At 12 months	2	72	Mean Difference (IV, Fixed, 95% CI)	‐0.40 [‐2.97, 2.17]
4 Serum ferritin ng/mL (change from baseline)	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
4.1 At 6 months	2	72	Mean Difference (IV, Fixed, 95% CI)	‐390.54 [‐819.00, 37.93]
4.2 At 12 months	2	71	Mean Difference (IV, Fixed, 95% CI)	‐247.78 [‐741.61, 246.05]
5 Liver T2* (m/s) (change from baseline)	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
5.1 At 6 months	2	65	Mean Difference (IV, Fixed, 95% CI)	‐0.71 [‐1.61, 0.18]
5.2 At 12 months	2	74	Mean Difference (IV, Fixed, 95% CI)	‐1.24 [‐2.76, 0.27]
6 Liver iron concentration (LIC) (mg/g) (change from baseline)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
6.1 At 6 months	1	50	Mean Difference (IV, Fixed, 95% CI)	‐1.64 [‐3.96, 0.68]
6.2 At 12 months	1	59	Mean Difference (IV, Fixed, 95% CI)	‐2.01 [‐4.84, 0.82]
7 Adverse events	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
7.1 Mild adverse events at 12 months	1	59	Risk Ratio (M‐H, Fixed, 95% CI)	8.71 [0.49, 154.89]