Usage
Diltiazem topical (2% cream or ointment) is primarily prescribed for the relief of pain associated with chronic anal fissures. It is classified as a calcium channel blocker. Diltiazem works by relaxing the smooth muscle of the internal anal sphincter, reducing anal canal pressure, and increasing blood flow to promote healing.
Alternate Names
Diltiazem hydrochloride is the chemical name. There are no widely recognized international variations for the topical formulation. Diltiazem is available under various brand names for oral formulations (e.g., Cardizem, Tiazac), but topical diltiazem is typically compounded and thus may not have specific brand names.
How It Works
Pharmacodynamics: Diltiazem inhibits calcium influx into vascular smooth muscle cells, leading to vasodilation and reduced muscle spasm. This reduces resting anal pressure and improves blood flow to the anoderm, facilitating fissure healing.
Pharmacokinetics: Topical application of diltiazem results in minimal systemic absorption. Though exact data is limited, studies suggest median plasma concentrations remain low after topical administration, minimizing systemic side effects. Elimination pathways for the small amount absorbed are primarily hepatic metabolism with renal excretion.
Mode of Action: Diltiazem binds to L-type calcium channels in the cell membranes of smooth muscle cells. This blockage inhibits calcium entry, preventing muscle contraction and leading to relaxation. This action on the internal anal sphincter is the primary mechanism for fissure pain relief and healing.
Dosage
Standard Dosage
Adults:
A pea-sized amount (approximately 2.5 cm strip of cream or ointment) is applied to the anal canal twice daily, typically for 6-8 weeks. Some protocols recommend application three times a day initially, followed by twice daily application.
Children:
The safety and efficacy of topical diltiazem in children have not been fully established. Some studies suggest its use in children, but a pediatrician should guide dosing based on age and weight.
Special Cases:
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Elderly Patients: No specific dosage adjustments are required, but monitoring for potential side effects like dizziness is important.
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Patients with Renal Impairment: Due to minimal systemic absorption, dose modifications are not usually necessary.
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Patients with Hepatic Dysfunction: Caution is advised. Closely monitor for potential systemic side effects.
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Patients with Comorbid Conditions: Patients with cardiac conditions should be monitored closely for potential, though rare, systemic effects.
Clinical Use Cases
The clinical use case for topical diltiazem is specifically for chronic anal fissures. Its use in other settings like intubation, surgical procedures, mechanical ventilation, ICU, or emergency situations is not applicable for the topical formulation. Intravenous diltiazem is utilized in those scenarios.
Dosage Adjustments
Due to minimal systemic absorption with topical application, dose modifications are not usually necessary based on renal or hepatic dysfunction.
Side Effects
Common Side Effects
- Headache
- Dizziness or lightheadedness
- Localized anal itching, burning, or irritation
Rare but Serious Side Effects
- Allergic reactions (rash, itching, swelling, severe dizziness, trouble breathing)
- Significant drop in blood pressure (hypotension)
- Severe bradycardia (slow heart rate)
- Worsening of heart failure
Long-Term Effects
No long-term adverse effects specific to topical diltiazem have been reported.
Adverse Drug Reactions (ADR)
Clinically significant ADRs are rare with topical application due to limited systemic absorption. However, immediate medical attention is required if any signs of allergic reactions, significant hypotension, or severe bradycardia occur.
Contraindications
- Known hypersensitivity to diltiazem.
- Patients with severe hypotension or bradycardia.
- Second or third-degree atrioventricular block (unless a pacemaker is present).
Drug Interactions
Clinically significant drug interactions are unlikely with topical diltiazem due to minimal systemic absorption. However, caution is advised when used concomitantly with other medications metabolized by CYP3A4, although interactions are expected to be minimal. Concomitant use with other antihypertensive medications might have an additive effect.
Pregnancy and Breastfeeding
Diltiazem topical is generally considered safe during pregnancy and breastfeeding due to limited systemic absorption. There are no adequate and well-controlled studies in pregnant women. While trace amounts may be present in breast milk, they are not considered clinically significant. However, it is always prudent to consult with a physician before use during pregnancy or breastfeeding.
Drug Profile Summary
- Mechanism of Action: Calcium channel blocker, relaxes internal anal sphincter.
- Side Effects: Headache, dizziness, local irritation.
- Contraindications: Hypersensitivity, severe hypotension/bradycardia, AV block.
- Drug Interactions: Limited potential due to minimal systemic absorption, caution with CYP3A4 substrates and other antihypertensives.
- Pregnancy & Breastfeeding: Generally safe due to minimal absorption.
- Dosage: 2.5 cm applied topically twice daily for 6-8 weeks.
- Monitoring Parameters: Blood pressure, heart rate (for patients with cardiac conditions).
Popular Combinations
Topical diltiazem is sometimes combined with lidocaine or other local anesthetics in compounded formulations to provide enhanced pain relief.
Precautions
- Monitor for local irritation or allergic reactions.
- Caution in patients with pre-existing cardiac conditions.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Diltiazem Topical?
A: Apply a pea-sized amount (2.5 cm strip) twice daily to the anal canal for 6-8 weeks.
Q2: How does Diltiazem Topical work for anal fissures?
A: It relaxes the anal sphincter muscle, reduces pressure, improves blood flow, and promotes healing.
Q3: What are the common side effects?
A: Headache, dizziness, and local irritation.
Q4: Can pregnant or breastfeeding women use it?
A: Generally considered safe due to minimal systemic absorption, but consultation with a physician is recommended.
Q5: Are there any drug interactions I should be aware of?
A: Drug interactions are minimal due to limited absorption. Caution is advised with CYP3A4 substrates and other antihypertensives.
Q6: How long does treatment typically last?
A: 6-8 weeks, but it can be longer depending on individual healing.
Q7: When should I avoid using Diltiazem Topical?
A: In cases of known diltiazem allergy, severe hypotension, significant bradycardia, or certain heart conditions.
Q8: What if I miss a dose?
A: Apply the missed dose as soon as you remember, unless it is close to the next scheduled application. Do not double the dose.
Q9: Are there alternative treatments for anal fissures?
A: Yes. Topical nitrates (like nitroglycerin ointment), botulinum toxin injections, or surgery are possible options. Lifestyle modifications like increasing fiber intake and using stool softeners are also important.
