:hi: Lars,
I found the following info on at netdoctor.co.uk about Rectogesic. I believe this is similar or the same as some of the ointments available in the US, like nifedipine or nitro and others which reduce the pressure.
"[color=darkblue]The ointment is applied inside the anus. It works by releasing a chemical called nitric oxide, which is a chemical also made naturally by the body. Nitric oxide relaxes (dilates) blood vessels. It also relaxes the internal sphincter muscle in the anus. This improves the blood supply to the anus, which relieves the pain and helps the fissure to heal."
"Although this medicine acts locally when applied to the anus, it is also absorbed into the bloodstream and can therefore have effects on the rest of the body. In particular, it can cause headaches. It may also cause a drop in blood pressure, especially when you move from a lying or sitting position to sitting or standing. The drop in blood pressure can make you feel dizzy or unsteady. To avoid this try changing position slowly. If you do feel dizzy, sit or lie down until the symptoms pass. If affected you should avoid performing potentially hazardous tasks such as driving or operating machinary. Drinking alcohol is likely to enhance any dizziness."[/color]
I have used the nifedipine for about 3 months and think it has helped me.
Hoping you are feeling better very soon.
Jo