The active ingredient in La Pela is tadalafil, same as in 1/2 of a Cialis. Kamagra is the sildenafil citrate (Viagra) equivalent.
Here's the thing. Anyone who has never taken prescription Viagra of prescription Cialis really shouldn't fool around with the Dominican OTC equivalents. These medications were discovered during trials for heart medications and their desired effects were listed as side effects during the initial drug trials. Anything that alters your heart rhythm or blood pressure should not be tried without prior physician supervision.
In the USA, Guys over 50 are offered free samples of both and these Levitra (vildenafil) after routine checkups if they are found in good health. Doctors get paid bounties by the pharmas to give this stuff away, just like dope dealers on the street offering samples to prospective new users.
Those pills sell for about $15-$20 each in the USA. It's not inconceivable for Guys to get a prescription for a bottle in the D.R. (how difficult is that? LOL) and sell them for 100%-500% profit in the States, paying for their entire trip including the 2-3 pills they may have taken while in country.
I recommend leaving the pills alone and trying the mamajuana. I have never heard of anyone going blind, having a stroke or dying from it.