The Effect of Intra-anal Nifedipine, Used As Add-on to Conservative Therapy, on Pain in Patients With Anal Fissure

Inclusion Criteria: \- Subjects meeting the following criteria will be eligible to participate in the trial: 1. Single anal fissure; 2. Signed written informed consent; 3. Male or female subjects 18 to 65 years of age inclusive; 4. Has chronic anal fissure defined as history of rectal pain at least three days a week for at least 6 weeks - or more AND at least one of the following: * Sentinel skin tag * Hypertrophied anal papilla * Exposure of the underlying internal anal sphincter * Anal cicatrisation 5. Visual analogue scale of average 24 hours rectal pain (VAS) of \> 40 mm in screening visit 6. Capable of using the IVRS and able to adequately communicate comprehension of the IVRS questions to the investigator 7. If female, is non-lactating, has a negative urine pregnancy test result, and does not plan on becoming pregnant during the study, or not of childbearing potential (hysterectomy or tubal ligation at least 6 months prior to entry to the study or post-menopausal for 1 year); if of childbearing potential (including peri-menopausal women who have had a menstrual period within one year) must practice or be willing to continue to practice acceptable birth control from screening and until 1 week after the study medication has been discontinued. Acceptable birth control includes : * combined (estrogen and progestogen containing) hormonal contraception * associated with inhibition of ovulation; oral OR intravaginal OR transdermal. * progestogen-only hormonal contraception associated with inhibition of ovulation: oral OR injectable OR implantable. * progestogen-only oral hormonal contraception, where inhibition of ovulation is not the primary mode of action * intrauterine device (IUD) * intrauterine hormone-releasing system ( IUS) * bilateral tubal occlusion * vasectomised partner * sexual abstinence * male or female condom with or without spermicide * cap, diaphragm or sponge with spermicide Exclusion Criteria: * Subjects are excluded from participation in the study if any of the following criteria apply: 1. Known allergy to Nifedipine 2. Unwilling to stop all other concomitant topical preparations applied in and around the anus from screening through the end of the study 3. Subfissure injection of botulinum toxin in the 3 months prior to screening. 4. Fissure resulting from inflammatory bowel disease, venereal disease, perianal psoriasis, immunodeficiency syndrome 5. Atypical fissure (occurs off the midline) in which secondary causes were not excluded. 6.…