Citrulline might do the same factor, although it works in a distinct strategy to Viagra. This suggests that growing ranges of either citrulline or arginine, or each might improve erectile function. Just two of the men taking a placebo saw their erections return to normal hardness ranges. Medications which will cause greater sildenafil ranges embody ritonavir (Norvir), clarithromycin, and ketoconazole. While Viagra, recognized clinically as sildenafil, may be the very best recognized ED pills, there are different FDA-permitted medications. There are additionally mixtures of the above medications available. However, there are plenty of doubtlessly dangerous options that folks have tried, including the injection of Vaseline or different petroleum jelly products into the penis. Some folks have had success using herbal supplements to treat ED. At first of the 1990s, researchers had been conducting experiments with sildenafil to see whether the brand new drug might deal with chest ache brought on by diminished blood circulation to the heart.