This study was designed to compare the effect of topical
glyceryl trinitrate (GTN) and oral
nifedipine treatments on maximal anal resting pressure (MARP) and subsequently to assess their effectiveness in healing of chronic
anal fissure (CAF). Patients were allocated randomly to receive either oral
nifedipine retard (10 patients) 20 mg twice daily or instructed to apply
glyceryl trinitrate (0.2 percent)
ointment (10 patients) into the lower half of the anal canal twice daily. They were reviewed and assessed at the first visit and every fortnight for measurement of MARP,
pain scores, blood pressure, pulse rate, healing of the fissure and adverse effects. Treatment were continued until healing had occurred or for up to 8 weeks. MARP values before and after application of the GTN
ointment was 113.2 cm H2O and 72.5 cm H2O respectively (P < 0.001).
Nifedipine caused a reduction in mean MARP from 105.2 to 74.0 cm H2O (P < 0.001). Linear analogue
pain scores were significantly reduced after 2 weeks treatment with GTN and
nifedipine (P < 0.001) and continued throughout the treatment period. At the end of the study; 7 of the 10 patients in the GTN group were deemed to be healed (5) or improved (2), compared with 6 of the 10 patients in the
nifedipine group (5 healed, 1 improved).
Headaches occurred in 3 patients in the GTN group, compared with one patient in the
nifedipine group. There was no significant difference between GTN and
nifedipine in terms of reduction in MARP and
pain score, healing of the fissure and incidence of early recurrence and side effects of treatments. We conclude that GTN
ointment and oral
nifedipine are equally effective in the treatment of chronic
anal fissure.