You can call your vet and ask for a refill on the GentaVed and see if they will do one without another office visit for now.
Here is a home made recipe for ear infection care
http://www.bichonfriseusa.com/ref/earsolution.htm
There are important things to know before deciding to use a medicine in a dog's ear.
You need to know if this is an infection or an ear mite problem as they are treated differently. I think you have it narrowed down to an infection.
You can read about infections here
http://www.marvistavet.com/html/body_ear_infections.html
and ear mites here
http://www.marvistavet.com/html/body_ear_mites.html
You need to know if the ear drum is perforated or not as most over the counter meds are not safe if that is the case.
You need to know if this is something that will clear up with topical meds, require oral meds, or is related to a problem with allergies or a thyroid problem.
If you know the problem is an ear infection and that the ear drum is not perforated then there are some things you can use.
You can see if your local pet supply store carries Zymox with cortisone or find it online. I've had good luck clearing up infections with that. You can read about it here http://animalpetdoctor.homestead.com/Zymox.html I would also suggest trimming the hair out of the ear so more air can circulate. Just be careful not to snip any ear while you do that. This site goes over ear infections and has another ear cleaner mentioned that had good results http://www.dermapet.com/articles/art-03.html here is just the product info http://www.dermapet.com/prod-09.html Ear infections are a common symptom of allergies in dogs. You can read about allergies and dermatitis in dogs here http://www.lbah.com/allergy.htm
http://www.priory.com/vet/vetatop1.htm Dogs can develop allergies to foods, and to inhaled items, and contact allergens such as rug cleaners, cedar beds, or chemicals including lawn chemicals or even flea bites. You might want to try a different dog food that has no ingredients the same as what you feed now. Wellness Fish and Potato works for many dogs for example. You might want to see if some plain Benadryl helps with the itching. A usual dose is 1mg per pound of dog. If you choose to use that please read here about cautions
http://www.petplace.com/drug-library/diphenhydramine-benadryl/page1.aspx
Or you may want to consult with your vet and consider doing allergy testing. Dogs can also be prone to low thyroid problems which can trigger allergies and infections. A vet can test for that issue too.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics