Now you are taking the equivalent of roughly 0.225mg of synthroid -- that's a pretty big increase all at once -- perhaps the labs indicated that you were very hypothyroid even on a good dose (0.125mg) and this is why the dose was increased like this. Some people do okay on combo synthroid and armour, I usually use synthroid and cytomel combo if I am interested in combination T4/T3 therapy. Side effects -- effects of excessive thyroid hormone, such as palpitations, tremors, anxiety, insomnia, etc.