Any reliable OTC meds to help asthmatic adults?

No. See your doctor and don't underestimate the serious nature of asthma.
No. Asthma is a chronic inflammatory condition of the lungs that vary in severity from very mild to deadly. Treatment depends upon the severity of asthma on has and includes inhalers that deliver broncodilators and / or steroids. Primatene was available otc but has been removed from the market.