Will combining drops with inhalations with saline have an adverse effect on the body?

Since there is no such drug as "Metamin", I suppose you mean Metmin. If so, please read on. There are no contraindications to use saline in the form of inhalation during therapy with the nasal drug Metmin. Salt in a concentration of 0.9% only cleanses and moisturizes the mucous membranes and should not interact with other drugs. Nevertheless, I suggest that you keep the right order and spacing. Inhalation with salt is best done first or during the day. I would suggest using Metmin as a second product or applying it at a different time. Metmin is a prescription drug, so its use and method of administration should be determined by the doctor: https://www.gdziepolek.pl/produkty/88706/metmin-aerozol/apteki/w-warszawie I attach information that may be of interest to you: https://www.gdziepolek.pl/artykuly/jak-prawidlowo-wykonac-inhalacje https://www.gdziepolek.pl/artykuly/czym-sie-rozni-nebulizator-od-inhalatora https://www.gdziepolek.pl/artykuly/jak-stosowac-krople-do-nosa https://www.gdziepolek.pl/artykuly/czy-sterydy-sa-bezpieczne