Panama City 4 hour lay over

I doubt it. So often flights are delayed in arrival, and then you would need to exit through immigration (with all the other hundreds of people going through Immigration), and then re enter through security and be at your gate in a timely fashion. Why not see what the airport itself has to offer? Mani/pedi, spa, day pass for an airline lounge, etc.
It looks like the airport official website is only available in Spanish. http://www.tocumenpanama.aero/
Alternative is: https://www.sleepinginairports.net/casa/panamacity.htm

Also, you require a tourist card for Panama....is it all worth it?

I wouldn't leave the airport with only 4 hours.

Thanks all. I forgot about customs. Guess we will hang out in the airport.

Thanks again

Dot

If you had a little more time you could have taken a cab (expensive from the airport as I recall) to either Casco Viejo or the Panama Canal or both. 4 hours will be cutting it close especially since the ride from airport to town is at least 30 mins if my memory is correct. The Canal is even further from the airport.

I don't recall any tourist card requirement when entering Panama - just a stamp in the passport and passport control didn't take more than 15 minutes.

Definately not enough time. Traffic can be horrendous depending on time of day plus one has to exit through immigration/customs and then back through security twice. With eight hours, a private tour of the canal with its locks on the Pacific side and Casco Viejo are doable.