The imprint “85” on a round, white tablet corresponds to the medication sildenafil, specifically in the 20 milligram strength. This code, established by regulatory bodies like the U.S. Food and Drug Administration, allows individuals and healthcare providers to quickly determine the contents of a medication. This particular dosage is most commonly associated with the treatment of high blood pressure in the arteries of the lungs.
Identifying the Medication and Its Class
The chemical compound identified by the “85” imprint is sildenafil, often formulated as sildenafil citrate. While the active ingredient is the same as the medication best known by the brand name Viagra, the 20-milligram tablet is marketed under the brand name Revatio when used for a distinct condition. Sildenafil belongs to a group of pharmacological agents known as Phosphodiesterase type 5 (PDE5) inhibitors.
Sildenafil is a pyrazolopyrimidinone derivative that modulates vascular tone and blood flow. This chemical categorization dictates the drug’s function, which includes treating both erectile dysfunction and pulmonary hypertension.
Primary Medical Conditions Treated
The primary use of the 20-milligram sildenafil tablet is for the management of Pulmonary Arterial Hypertension (PAH). PAH is a progressive disorder characterized by high blood pressure in the arteries that carry blood from the heart to the lungs. The increased pressure strains the heart, leading to symptoms like shortness of breath, dizziness, and fatigue.
Sildenafil is used in adults diagnosed with PAH to improve their capacity for exercise and delay the clinical worsening of the disease. By relaxing the blood vessels within the lungs, the medication reduces the resistance the heart must overcome to pump blood. This effect lessens the strain on the right ventricle of the heart, which is a major goal in treating PAH.
The compound is also widely recognized for treating Erectile Dysfunction (ED). Sildenafil improves blood flow to the penis, which is necessary for a natural erection to occur during sexual stimulation. Although the 20-milligram tablet is specifically approved for PAH, the same active ingredient is used in higher doses for ED treatment.
How the Medication Works in the Body
Sildenafil exerts its therapeutic effects by specifically inhibiting the enzyme phosphodiesterase type 5 (PDE5). This enzyme is responsible for breaking down a substance called cyclic Guanosine Monophosphate (cGMP) within the smooth muscle cells of blood vessel walls. When physiological signals trigger the release of nitric oxide, cGMP levels increase, causing these smooth muscles to relax.
By blocking PDE5, sildenafil prevents the rapid degradation of cGMP, leading to sustained muscle relaxation and the widening of blood vessels (vasodilation). In the pulmonary arteries, this vasodilation lowers the blood pressure in the lungs, reducing pulmonary vascular resistance.
The same biological pathway is utilized to treat erectile dysfunction, where the drug targets the PDE5 enzyme concentrated in the spongy tissue of the penis. Prolonged cGMP levels lead to increased blood flow into the penis, resulting in a firmer erection. This action is dependent on sexual arousal, as sildenafil only enhances the natural physiological response.
Safe Dosage and Important Safety Warnings
For the treatment of Pulmonary Arterial Hypertension, the typical adult dosage for the 20-milligram sildenafil tablet is 20 milligrams taken three times a day. These doses are usually administered at intervals of four to six hours to maintain a steady concentration of the drug in the bloodstream. Dosage adjustments may be made by a healthcare provider based on the patient’s tolerance and response, but it is important never to alter the prescribed regimen independently.
A major safety warning associated with sildenafil is its absolute contraindication with any form of organic nitrate medication, which are often prescribed for chest pain. The combination of sildenafil and nitrates can cause a severe and rapid drop in blood pressure, leading to a life-threatening hypotensive event. Other drug interactions include riociguat, a guanylate cyclase stimulator, which is also strictly contraindicated.
Common side effects of sildenafil include:
- Headaches
- Flushing of the skin
- Upset stomach
- Nasal congestion
More serious, though rare, adverse reactions require immediate medical attention, such as priapism (an erection lasting longer than four hours and can cause permanent damage). Patients should also seek urgent care if they experience sudden loss of vision or hearing.