The only thing that I know of has been what I used - Avena Sativa tincture. You will need to be sure it's oats taken in the 'milky' stage to make this tincture. The one that I chose was Gaia Herbs:
www.gaiaherbs.com/products/detail/401/Wild-Oats-Milky-Seed-Certified-Organic- Although I do suggest shopping around for the best herbs, even if you choose to use Gaia Herbs brand.
This may take a week or more before you feel much difference though. Other than this, I never did find anything else that worked for longer than the 10 - 15 minutes either. I used a full dropper full (20 drops) 3 times a day.
Maybe others will have more suggestions if you don't want to use a tincture.