What medications are used to treat rectal spasms?

Medications for Rectal Spasms

For rectal spasms, calcium channel blockers (such as nifedipine) are the first-line pharmacological treatment due to their effectiveness in relaxing the internal anal sphincter with minimal side effects compared to other options. 1, 2

First-Line Treatments

• Topical calcium channel blockers (CCBs) such as nifedipine ointment are recommended as first-line therapy for rectal spasms due to their ability to relax the internal anal sphincter and enhance drainage with fewer side effects than other options 1, 3
• Treatment should be administered for at least 6 weeks, with pain relief typically occurring after 14 days of consistent use 1
• A prospective randomized study showed that topical 0.3% nifedipine with 1.5% lidocaine ointment applied every 12 hours for 2 weeks resulted in a 92% resolution rate of acute thrombosed external hemorrhoids compared to 45.8% with lidocaine alone 1

Second-Line Treatments

• Topical nitrates (glyceryl trinitrate) can be used as an alternative to calcium channel blockers for sphincter relaxation, but are associated with a higher incidence of headaches (up to 84% of patients) and hypotension 3, 4
• Botulinum toxin injection into the anal sphincter can be considered when topical treatments fail, causing temporary paralysis of the sphincter muscle for 2-3 months 3, 5
  • Success rates of 43-96% have been reported, but this approach is more invasive and expensive than topical treatments 2, 4
  • Minor incontinence for flatus and soiling has been reported in up to 12% of patients 4

Pain Management

• For pain control, integrate topical anesthetics (such as lidocaine) with common pain killers when pain control is inadequate 1
• Tricyclic antidepressants at low doses can be beneficial for rectal pain, particularly if it has a neuropathic component, but should be avoided if constipation is a major feature 1
• For neuropathic rectal pain, adjuvant analgesics may be particularly effective 6

Muscle Relaxants

• Cyclobenzaprine, a muscle relaxant, has shown effectiveness in treating levator ani syndrome (a condition involving rectal spasms) at doses of 5 mg three times daily 7
• The mechanism appears to involve influencing α and γ motor neurons in the central nervous system, leading to attenuation of muscle spasm 7

Procedural Interventions

• Controlled anal dilatation techniques (balloon dilatation and staged dilatation) may be considered before surgical treatment for chronic conditions, showing healing rates comparable to internal sphincterotomy with near-zero complication and incontinence rates 1
• Surgical sphincterotomy should be reserved for cases that fail to respond to pharmacological management due to the risk of fecal incontinence 2, 4

Important Considerations

• Manual dilatation of the anal sphincter has been abandoned due to high risk of temporary (30%) and permanent (10%) incontinence 1
• Steroid creams should be applied for no more than 7 days, as long-term use can cause thinning of perianal and anal mucosa, increasing risk of injury 1
• For patients with rectal spasms related to irritable bowel syndrome, antispasmodics with anticholinergic action (such as dicyclomine and hyoscine) appear to be more effective than direct smooth muscle relaxants (mebeverine and alverine citrate) 1

By addressing the underlying hypertonicity of the internal anal sphincter, these medications can effectively relieve rectal spasms and associated pain while minimizing the risk of complications that can occur with more invasive interventions.