Hi all, I wonder if anyone else has experienced this?
After taking nifedipine for 2 months with no healing and no pain relief, my colorectal nurse wrote me a prescription for diltiazem. It seemed more effective right from the start and I got pretty hopeful. With fibre and lots of water, the fissure was pretty manageable.
BUT!!!! after about 3 weeks, I noticed itching, lumpiness and rash.  
After a couple of days of this I realized that my anus was always slightly wet and my underwear slightly stained. I think the itchiness was caused by the wetness. Maybe the liquid is irritating. After a few days, the wetness was so bad I had to wear a pad. Also, applying the diltiazem really burned. Ow ow ow, I have enough going on down there without that!!!!
I stopped the diltiazem on Saturday, and today (Monday) the leakage has stopped. Good news! BUT!!!! I now have a HORRIBLE rash all over my buttocks, up on my stomach and down my thighs. This MIGHT be from the desitin that I used to try to soothe the itch, which I admit is very old (the babies I bought it for are now 11 and 15).
Has anyone else experienced anal leakage with diltiazem? It really kills me that my sphincter must be relaxed enough to leak, while being so tight that I still get pain with BMs. The doc calls it pruritis ani, but this just means itchy anus and has lots of causes. He didn't answer my question, can diltiazem cause leakage. He said use calmoseptine and keep on with diltiazem.
Any advice, anyone? I have to admit I was in tears when I emailed the doc.

OK, so I stopped using Diltiazem 4 days ago. The wet anus is still totally cleared up. No more leakage. However, I still have an itchy rash all over my torso, arms and legs. I saw a doctor today (GP, not CRS) and she agrees with me that it's a strong reaction to diltiazem. I had googled diltiazem rash and found out that it can cause whole-body rash, though very rarely.
So - nifedipine doesn't work for me. Diltiazem seemed to help but now I can't use it any more. I want to try the tri nitroglycerine, but they are very reluctant to prescribe that here, because of headaches. I am seeing the colorectal nurse practitioner on Friday, and I'll try to talk her into it. It's my head and my butt, and I want to risk the headaches.  
I don't see the CRS to talk about LIS until late Sept. That gives me 6 weeks to try to heal with drugs and diet and without surgery.
Wish me luck!

Oh Scientist!
Wishing you all the very best of luck with your forthcoming 6 weeks....
As soon as I read your original post, I pretty much guessed you were one of the unfortunate few with a major reaction to the Diltiazem and that was confirmed by your following post - I'm sorry to hear that especially since you thought it seemed to be helping you too.
Recto does affect a lot of people but there are ways of dealing with it. It's more of a head rush sensation that you experience and your head just seems to pound for a while but I found applying it at night before bed was OK because I'd just sleep it off and in the morning, I noticed it less because you kind of have to get on with your day anyway, so can be more distracted from the sensation. On saying that, I really didn't like it and was relieved by switching to the Diltiazem.
I would say it's definitely worth the "risk" if it can help heal your fissure, before you start having to consider LIS as your option (moreso, as you noticed results with Diltiazem)
There is always Botox too, which a lot of people are finding very helpful right now??
I wish you all the very best in dealing with the issue in the next few weeks and would suggest using vaseline as a pre BM lubricant in that area as that's really helpful..... obviously be really strict to keep a super-soft stool diet and drink loads and stay on top of the painkillers if you need them. Hopefully, you will resolve your issue through conventional methods alone and surgery may not then be an option for you anyway....:) 

I saw the colorectal nurse, and she was pretty shocked by the state of my poor buttocks, bright red and peeling from the rash. There was still visible rash on my legs too. She prescribed the nitro without any argument, but recommended me not to start using it until the rash was completely gone. I just tried my first dose of it today. It's 0.2% nitro, and I'm supposed to use a pea-sized amount, but I only put on about a lentil sized amount :D . That was in the morning. No headache, no head rush, probably because the amount was so small.
So what I think happened with the Diltiazem was that it irritated my skin and  caused the skin around my anus to weep fluid. That fluid made the whole area itchy and irritated further, causing me to scratch, causing more irritation, causing more weeping of the skin........don't know why it took over my whole body though.
The funny thing is that ever since I gave up the diltiazem I've had only a little pain, more discomfort really. Sometimes the mornings are not so great, but it's NOTHING like the pain I had all day and sometimes all night in the first few weeks of fissure. I wonder if sticking my finger up inside was doing more harm than good? I'm not going to put the nitro inside. I'm just going to dab it on the fissure. Nitro is very well absorbed through the skin. After all, if it can get all the way to your head to cause headaches, I'm sure it can cross from external skin to internal sphincter!