My non-expert non-medical advice would be to just focus on feeling better and don't worry about ketosis. You can always get back into ketosis later. For my last cold I got sugary cherry cough drops because IMHO the sugar-free ones taste like kittens.

Not saying having a cold or whatever is an excuse to blow all the limits, just don't get hung up on a few g of carbs in the medicine.

I get the yogi cold teas. They help tremendously. Also, sugar free cough drops if needed. Or slippery elm. Or cherry bark. But I'm a bit witchy with the herbs.

Ginger and lemon tea helps a lot. I use the sugar free one, they work as well as the ones with sugar. If my problem is allergies and I have itching eyes as well, I do have the G&L tea with local honey added. Nothing seems to work on that part of my allergies as much as local honey does, even prescription meds fail when it comes to my itching eyes. My honey comes from a hive within 4 miles of my home. So it really is local.

If I remember correctly, my homeopathic (totally against western medicine) aunts would use black pepper and chocolate to treat coughs. I mean they would literally give you black pepper by the spoon full. Dark Chocolate has some compound in it that also helps sooth coughs..I can't remember what it is though. Belladonna and Ferrum tablets can also be used to treat cough but if you've never spent time in the homeopathic remedy world I'd suggest having an experienced practitioner help out. Or, at the very least ask for some assistance upon purchase and read the labels very carefully.

I hope you get feeling better soon! I will also say that there are non-medicinal ways to help a cough, and coffee is personally my favorite Like everyone is saying, focus on getting better and you can always kick back into ketosis when you're feeling a bit more like yourself!

Nyquil has ~100calories per dose IIRC so steer clear of that too. My mind was blown when I found that out.