Ask your pharmacist for a list of the ingredients. How should this medicine be used? Some people may also have ringing in their ears tinnitus or dizziness. It will not contain in its formulation substances with narcotic or psychotropic activity. Your doctor will tell you not to take sildenafil if you are taking street drugs containing nitrates. Regulatory requirements for OTC medications are the same as for prescription drugs, i. This increased blood flow can cause an erection.The generic name for Viagra is sildenafil. The drug also has another brand name: Revatio. It works by slowing down the action of PDE5, an enzyme in the blood vessel walls.. This enzyme breaks down. 1 SAV – South America Voyager Medellin, Colombia Destination Expert for Colombia, Ecuador, Medellin, Bogota, Cartagena Level Contributor 7, posts reviews helpful votes 1. Re: Is Sildenafil (Viagra) in Bogota??? 3 years ago Save Yes available . Save. Cialis and Viagra are not sold over the counter. You need a prescription. You may see a doctor and get a prescription, or try and buy with no prescription in a farmacia. Even though they are supposed to request a prescription, well, this is Colombia. You have the local Sildenafil 50mg 4 tablets around 7, pesos.