Is it something dangerous if I missed a dose of Amotaxi and what to do if the antibiotic runs out?

From the point of view of the effectiveness of therapy, skipping a dose is not beneficial. If the "missing" took place yesterday, however, nothing can be done about it - do not use a double dose to make up for the missed dose. If you were prescribed Amotaxi at a dose of 2 x 3 ml = 6 ml per day, you probably received a prescription for a package of granules to make 60 ml of suspension (60 ml and 100 ml packages are available). A pack of 60 ml should be enough for 10 days of treatment with the correct preparation of the suspension and precise dosage (60 ml : 6 ml per day = 10 days). It seems to me, therefore, that it requires an explanation of why you think that the drug will "definitely be missing", especially since one of the doses was not taken and generated a certain supply of medicine. In my experience, the pediatrician generally prescribes the amount of the drug that is supposed to be enough for the entire treatment. I would also like to draw your attention to the information from you that the drug was to be used "up to 10 days". This is not exactly the same as "for 10 days". The first phrase suggests that the treatment may last less, but at the same time no more than 10 days. Accurate information on the duration of treatment should be provided by the pediatrician and may depend on the effect of treatment obtained. If, despite the above explanations, you think that you need medicine to continue treatment, I suggest you consult a doctor about receiving a prescription: https://www.gdziepolek.pl/telekonsultacja https://www.gov.pl/web/zdrowie/tpk https://www.gdziepolek.pl/produkty/4818/amotaks-tabletki/apteki/w-warszawie