I have posted previously an anecdotal story of the dangers of Viagra overdose (see "Cunning Conversations - Viagra is Not for Boys" on "TheCunningLinctus.blogspot.com"), but I now write from personal experience about "normal" use.
Firstly let me reiterate that Viagra and related Cialis are prescription medications, since there are medical conditions that contra-indicate their use (certain heart conditions). Always have a doctor's consultation first. These medications are prescribed for Erectile Dysfunction and if you don't suffer from ED, then their use just for the 'high' is unwise.
I was in my late 50's when I first started suffering the embarrassment of 'running out of steam' mid-stream (if you will excuse the mixed metaphors). My doctor first tried me on one 100mg dose of Viagra with wonderfully hard results (but followed by side effects described below). I also then realised that the hard coating made the tablet impossible to break in half. I then tried a 50mg dose with almost as good results and less side-effects.
Considering their cost (around AU$70 for a packet of 4, and 50mg and 100mg sizes are around the same price - but do shop around since the price varies quite a bit between pharmacies) - I opted for the 100mg dose and use a craft knife/saw to cut them in half, thus effectively halving my per dose cost. I have tried Cialis recently, but they seem to come in only one size which are a lot smaller and cannot be cut - they cost around AU$140 for a pack of 8. There are also on-line/mail-order suppliers, but I'm suspicious.
The chemical's excretion rate is slower with age, so at 60 one can enjoy the effects for a good 24 hours (remember you need to take your tablet at least 30 minutes before 'required'). It's so nice to wake up the morning after with a hot hard-on - better yet if you have someone to share it with - sigh, no such luck for me.
There is a myth that you end up with a 'permanent' erection (for the duration) - this is false - you will be 'full' but flaccid until 'stimulated'. You will be slow to come down after ejaculation (so be careful your lady-friend doesn't continue to enjoy herself and end up with a condom slippage). You will probably also find your self ready for round 2 (or 3) sooner (decreased “refractory” period).
With Erectile Dysfunction, you may also have started losing sensitivity and take longer to come (if at all). Viagra/Cialis does NOT help this. So you may find that you can keep going for as long as your lady is up for it - forget the 'happy ending' and enjoy the journey.
Side effects are dose dependant and vary between users - some people claim Cialis has fewer side effects.
The first side-effect is flushing of the skin, particularly of the face - no big deal - but might be a 'give-away' to the wife!
Head-aches are common after 3-4 hours and doubly so with alcohol.
Intestinal gastric effects also occur, being gastric reflux (indigestion) and next day what I call "Teflon bowel".
If you have a predisposition to peripheral capillary bleeds (nose or haemorrhoids) there is a chance you might suffer a minor bleed.
Then there is the chance of condom 'accident' described above.
Absolutely the best thing ever. It will keep me going into my 70s for as long as I can afford it (and the ladies).
Wishing you all a very Happy, Hard New Year.
Wikipedia (http://http://en.wikipedia.org/wiki/Sildenafil) has an excellent, full write-up and lots of references for more details).