The intersection ‘Santa Beatriz’ in central Lima is a 20-30 min- ute cab-ride from the tourist area of the Miraflores, depending upon the traffic. (In Lima, taxis are cheap with the average rate per hour costing between 25 and 30 Peruvian soles. Hotels routinely organise cabs for guests which is one way of guar- anteeing guest safety for the inexperienced traveller). While, in the past, the biggest of these stores - Zoo Farma - has sold Halatal freely over the counter, a prescription is now needed. This is also the case for the Agro Suni store. However, there are others who will sell it.
While the feedback below was first provided in 2015/16, it has been confirmed as accurate in 2020. The green and white building should be your first port of call.
I went to Lima a few days ago and stayed at Miraflores. The Estadio Nacional is a short 12 soles ride (local drivers will often try to scam foreigners into paying 20+ soles). Neither AgroSuni nor Zoofarma would sell me Nembutal. Both had Halatal on display, but their sellers refused to sell me without a prescription.
There is, however, a third Agroveterinaria there. It´s a small place, without a name (or, at least, I could not find its name) a few meters to the right of AgroSuni (Zoofarma being a few meters to its left). (Ed’s note - or around the corner from Zoo Farma)
First time I went there the seller just told me to come back the following day, after 14:00. I went there at 14:45 to find a sign stating the store was closed from 13:30 to 14:30. It opened at 15:00. After he saw me, the seller tried twice calling someone over the phone while dealing with the other customers (the place was full, with a bigger number of customers than AgroSuni), with no success.