For PE (Premature Ejaculation), a lot of different drugs will work like any opiod, tramadol, most anti-depressives (one is preferred for PE), and as johnsmithisnotgreat discovered it's easy to take too much, and then you're fucked, so to speak, because effects last 1-4 days, so you also might not like how it makes you feel.
Also, the drugs that prolong ejaculation may make it harder to get hard. Some guys, like porno studs, can develop mental control to prevent cumming except when desired, but usually with limited stimulation.
Basically, you have to experiment starting with small doses of PE drug, as little as 1/4 of drug minimum dose. I use tramadol, because I take it for another condition. Keep in mind, that tramadol can take 2-3 hours to kick in.
The common PE prevention technique that mongers mention in reviews, is to stop screwing before cumming, but you often got to do it before like the last 5-20 seconds when it's too late to stop it. The providers are often used to this, since many guys are one shot (takes more than 1/2 hour to recover), and will hold off cumming by stopping or changing positions until last 10 minutes of session. Typically you can tell the provider to stop and go, like with bj or cg.
To shorten refractory period, you need to keep prolactin from increasing after cumming. The drug cabergoline will do this, which I have heard porno studs will take for quick recovery after cumming. It can be legitimately prescribed if you are anorgasmic, have difficulty cumming. But I don't know why, to improve sexual experience, guys can't get a prescription to shorten refractory period, like if you have a multi-orgasmic girl friend.
Considering how much we spend on quality Kgirls, it makes sense to get the most out of the sexual experience with the right drugs.