You can check through the website of the Colegios of Pharmacists in Spain.
You simply enter the name of the meds, execute the search and click on one of the results. A new screen will open where you will see information on yes/no covered by INSS, subject to co-pago, when it was first authorised for sale in Spain etc.
If you press the icon ´consejos al paciente´ in the top toolbar, it will show a screen with recommended dosage or caution for use during pregnancy for example.
If there are any warnings, such as ´will influence capicity to drive a vehicle ´ they will appear under ´advertencias´ if applicable.
The only thing I´ve not been able to change is the Autonomous Region, so the ultimate check on yes/no covered by Seguridad Social would be your medico or Farmacia, but this website gives a useful indication.