Diltiazem 2% rectal ointment is a compounded, prescription medication applied to the anal area. Diltiazem is a calcium channel blocker that, when applied to the anal area, relaxes the ring of muscle around the anus (the internal anal sphincter). Providers most often prescribe it for anal fissures, which are small tears in the skin of the anal canal that can cause sharp pain and bleeding with bowel movements. It is prepared by a licensed pharmacy to the strength and form your provider orders rather than mass-produced, and Bayview compounds it as both a 2% ointment and a 2% gel.
Diltiazem taken by mouth is an FDA-approved medication for blood pressure and chest pain, but there is no FDA-approved diltiazem product for use on the anal area in the United States. The rectal ointment and gel are available only through compounding. Professional guidelines for colon and rectal surgeons recognize topical calcium channel blockers like diltiazem as a first-line, non-surgical option for chronic anal fissures.
How does it work?
Most anal fissures hurt and heal slowly because the internal anal sphincter tightens and goes into spasm. That constant tension squeezes the small blood vessels that supply the torn skin, reducing blood flow and keeping the tear from healing (StatPearls, Anal Fissures). Diltiazem is a calcium channel blocker. Applied directly to the anal area, it relaxes that muscle, which eases the spasm and pain and allows more blood to reach the tissue so the fissure can heal (NICE evidence summary). Because it is applied to a small area of skin, only small amounts are absorbed into the rest of the body.
What is it used for?
Providers most often prescribe diltiazem 2% rectal ointment or gel for chronic anal fissures, meaning tears that have not healed after about six weeks of home care such as fiber, fluids, and warm sitz baths. The 2023 clinical practice guideline from the American Society of Colon and Rectal Surgeons notes that topical calcium channel blockers heal chronic fissures about as well as topical nitroglycerin but cause fewer side effects such as headache, and can be used as first-line treatment (ASCRS 2023). Some providers also consider it for other conditions involving anal muscle spasm, such as pain after hemorrhoid treatment or episodes of rectal muscle spasm. Only a licensed provider can decide whether this formulation is right for a person; Bayview Pharmacy does not provide consultations or determine appropriateness, and a valid prescription is required.
How do the forms compare?
Both forms contain the same strength of diltiazem (2%) and are applied to the same area. They differ in the base, which affects how they feel and spread. The table below describes those differences for education only.
| Form | How it's used | Notes |
|---|---|---|
| Rectal ointment | A small amount applied to the anal area as directed | An oil-based, petrolatum-style base that stays in place and can protect the skin |
| Rectal gel | A small amount applied to the anal area as directed | A water-washable base that spreads easily and feels less greasy |
Differences in form and base are described for education only and are not a statement that any option is better, stronger, or more effective. Your provider determines which form and dose are appropriate for you.
How is it used?
Diltiazem rectal ointment or gel is used following the exact schedule and amount set by your prescriber. A common direction is to apply a small, pea-sized amount to the anal area twice daily, and some providers direct use after bowel movements as well. Treatment often continues for six to eight weeks so the fissure has time to heal, even if the pain improves sooner. Apply it with a fingertip, a glove, or a finger cot as directed, and wash your hands before and after use. Use it only on the area your provider specifies, and never change your dose or stop early on your own. If you are unsure about how to use it or about your dosing, contact your prescriber, and a Bayview pharmacist is available if you have questions about your prescription.
Side effects & safety
Applied to the anal area, diltiazem is absorbed into the rest of the body only in small amounts, and studies report fewer headaches than with topical nitroglycerin, the other common topical treatment for fissures (ASCRS 2023). The most common effects are local, such as itching, burning, or irritation where it is applied, and some people notice a mild headache. Contact dermatitis, an itchy skin rash from the medication or its base, has been reported and usually resolves when the medication is stopped (NICE evidence summary).
Tell your provider about all medications you take, especially blood pressure or heart medications, including oral diltiazem or other calcium channel blockers, and share your full medical history so they can decide whether it is appropriate for you.
Seek medical care for signs of a serious reaction, such as fainting, a very slow or irregular heartbeat, severe dizziness, or a spreading rash or swelling.
Who should not use it?
Diltiazem rectal ointment or gel is not appropriate for everyone. It should not be used by people who are allergic to diltiazem or to any ingredient in the base. It is used with caution in people taking oral diltiazem or other blood pressure or heart rhythm medications, and in people with certain heart conditions such as a very slow heartbeat or low blood pressure, since even small absorbed amounts add to the same drug class. If you are pregnant, planning to become pregnant, or breastfeeding, talk with your provider before using it. Tell your provider about your full medical history and all medications you take so they can determine whether this formulation is appropriate for you.
How should it be stored?
Store exactly as directed on your label, at room temperature and away from heat, light, and moisture. Keep the cap tightly closed, keep it out of the reach of children and others in the home, and do not share it. Do not use it after its expiration or beyond-use date, and dispose of unused medication as directed.
Why is this compounded?
There is no FDA-approved topical or rectal diltiazem product in the United States, so compounding is the only way to obtain it. Compounding also lets a licensed pharmacy prepare the strength a provider selects and the base that suits the patient, for example an ointment that stays in place or a gel that washes off easily. Accurate strength matters for this preparation, and published testing of compounded topical diltiazem has found that quality varies between pharmacies, which is why it should come from a pharmacy with strong quality practices (IJPC study). As a 503A compounding pharmacy, Bayview Pharmacy prepares each order in small batches under USP <795> standards using quality ingredients. Compounded preparations are not FDA-approved.
Clinical details for prescribers
Regulatory status. Diltiazem HCl is not a controlled substance. Oral diltiazem is FDA-approved for hypertension and angina; no topical or rectal diltiazem product is FDA-approved in the United States, so perianal diltiazem is available only through 503A compounding. Compounded preparations are not FDA-approved.
Formulation (perianal dosing). Compounded as diltiazem HCl 2% in an ointment or gel base, dispensed in 30 g, 45 g, and 60 g quantities. Commonly reported dosing is a pea-sized amount (roughly 1 g) applied to the perianal area and distal anal canal two to three times daily for 6 to 8 weeks; some regimens add application after bowel movements. The 2023 ASCRS guideline recommends topical calcium channel blockers as first-line therapy for chronic anal fissure, with healing comparable to topical nitrates and a lower incidence of headache (ASCRS 2023). Systemic absorption from perianal application is limited.
Counseling / clinical points:
- Counsel patients to complete the full course even if pain improves early; chronic fissures typically need 6 to 8 weeks of therapy
- Pair with supportive care (fiber, fluids, sitz baths, stool softeners as appropriate)
- Most common adverse effects are perianal pruritus and irritation, headache, and occasional contact dermatitis; consider a base switch (ointment vs. gel) for local intolerance
- Review concurrent oral calcium channel blockers and rate-limiting cardiac medications
- Persistent or atypical fissures warrant re-evaluation for secondary causes (Crohn disease, infection, malignancy) (StatPearls)
Botulinum toxin injection and lateral internal sphincterotomy remain options after failed topical therapy per ASCRS. Background: StatPearls, Anal Fissures; NICE ESUOM3.
This is a prescription compounded medication and is not FDA-approved. This information is educational and is not medical advice. Your provider determines whether it is appropriate and sets the formulation and dose.
