I have tried both Viagra (sildenafil) and Cialis (tadalafil). They were not generic, since I am very concerned about purity and concentration. I have never tried Levitra (vardenafil).
The Viagra 50mg tablets work great for me, and take about 30 minutes on an empty stomach for good results. Cialis takes a bit longer to kick in, but the effect was pretty much the same, only longer-lasting. I did not have any of the side-effects that others have experienced, and am happy using the Viagra.
One drawback is that these pills are
EXPENSIVE! :frown1: I contacted my doctor, and asked him to bump up my prescription to the 100mg tablets so I could cut them with a pill splitter. I get pretty good results with only 25mg, making my per-dose cost about $2.25.
All three of these drugs work by inhibiting
cGMP-specific phosphodiesterase type 5 (PDE5).
Cyclic guanosine monophosphate (cGMP) relaxes the smooth muscles in arterial walls of the penis. cGMP is synthesized from
Guanosine-5'-triphosphate (GTP) by using
guanylate cyclase (GC) as a catalyst during periods of sexual arousal. After a man ejaculates, the enzyme, PDE5 begins breaking down the cGMP, and the erection subsides. It is neat a balancing act.
As men get older, the level of PDE5 tends to increase, resulting in various degrees of Erectile Dysfunction (ED), or impotence. By taking one of the above PDE5 inhibitors, many men are able to achieve a satisfactory erection. In my case, with Viagra, my erections are now as hard as they were when I was a teenager! :biggrin1: :biggrin1: :biggrin1:
Looking for a cheaper cost-per-erection, I did some research. An interesting finding was that taking 200mg of cimetidine (Tagamet - for heartburn) increased the blood plasma concentration of Viagra by 56%. As far as I could find (I am very careful about drug interactions), there was no additional side-effects by taking Viagra with Tagamet.
HOWEVER, the Viagra dosage should be reduced. I now take 25mg of Viagra with one 200mg cimetidine tablet. My erections are consistently very hard, and the effectiveness of the Viagra is now about 6 hours instead of the regular 4 hours.
:icon4: Since any of these ED drugs work by relaxing arterial smooth muscle, taking them with other nitrates (such as nitro-glycerine heart medication), can cause a dangerous drop in blood pressure. Some people take an illicit recreational nitrate drug known as "poppers". Using ED drugs in conjunction with nitrates can cause death.
:icon4: You should
avoid drinking grapefruit juice while taking Viagra, since it can delay the drug's absorption. Possibly leading to disappointing results.
:icon4: This message contains my findings, and should not be taken as advice to mix Viagra with cimetidine or any other drug or grapefruit juice. You should do your own research, and
always consult your doctor for medical advice.
Here's a link to the study of sildenafil "Viagra" and cimetidine "Tagamet" drug interactions:
The effects of cimetidine and antacid on the pharmacokinetic profile of sildenafil citrate in healthy male volunteers