What you need is to get your animal to a vet (any vet) and ask for the following
Get a culture and based on the culture the proper injectable antibiotic should be prescribed for no less than 30 days.
Do not play vet, your animal must be properly diagnosed and the proper antibiotic must be prescribed, there are more than one type of RI and this is why there is not a one fit all antibiotic, also do not prescribe an antibiotic just because or because you have access to it.
As for you asking for dosage recommendations keep in mind this is a dangerous game that could lead to dangerous advice which is not what we do here even if some of us are familiar with dosage.
Do not use home remedies that includes vicks and other essential oils you will do more damage than good.
A RI is not a human cold you are trying to alleviate with human remedies, it is something serious that needs to be treated with antibiotics.
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