If I stopped Venlectine for 10 days, do I have to start again with 37.5mg or can I continue to take 75mg?

This begs the question of whether you have discussed discontinuation of Venlectine with the doctor who ordered the drug. If so - it should indicate how to resume use. If not - the more you should consult a person who has more information about your disease and the course of current treatment. I suppose that it may be advisable to resume from a lower dose, but as I pointed out - the decision lies with the person supervising your therapy. Apart from certain situations (e.g. severe course, significant interactions with anti-infective drugs), viral infections, colds - are not an indication to discontinue therapy with psychiatric drugs, because it is a chronic treatment and generally requires many months of systematic use to obtain and consolidate the effect of treatment. Abrupt discontinuation of treatment (without dose reduction) with medicines such as Venlectine may also contribute to side effects. I enclose information that may be of interest to you: https://www.gdziepolek.pl/artykuly/czy-jak-i-kiedy-mozna-odstawic-leki https://www.gdziepolek.pl/produkty/81772/venlectine-kapsulki-o-przedluzonym-uwalnianiu/apteki/w-warszawie