Usage
Lidocaine + Nifedipine topical cream is primarily prescribed for the treatment of chronic anal fissures. It is a combination product belonging to the pharmacological classifications of local anesthetics (lidocaine) and calcium channel blockers (nifedipine). The mechanism of action involves a two-pronged approach: lidocaine provides local pain relief by blocking nerve signals, while nifedipine reduces anal canal pressure and improves blood flow to the affected area by relaxing the smooth muscles and dilating blood vessels. This combined effect promotes healing and reduces discomfort associated with anal fissures.
Alternate Names
There are no widely recognized alternate names for the combination of lidocaine and nifedipine. However, it is marketed under various brand names, including Anobliss Cream. The individual components have other names: lidocaine is sometimes called lignocaine, and nifedipine is available under brand names like Adalat and Procardia.
How It Works
Pharmacodynamics: Lidocaine acts locally by blocking voltage-gated sodium channels in nerve fibers, preventing the transmission of pain signals. Nifedipine, a dihydropyridine calcium channel blocker, inhibits calcium influx into smooth muscle cells, leading to vasodilation and decreased muscle contraction. This reduces anal canal pressure and improves blood flow, facilitating healing of the fissure.
Pharmacokinetics: Lidocaine, when applied topically, is absorbed into the systemic circulation to a limited extent. It is metabolized primarily in the liver and excreted by the kidneys. Nifedipine, when applied topically, also has limited systemic absorption. It is extensively metabolized in the liver, mainly by CYP3A4 enzymes, and excreted in the urine and feces.
Mode of Action: At the cellular level, lidocaine binds to the intracellular portion of voltage-gated sodium channels, blocking the influx of sodium ions and preventing nerve depolarization. Nifedipine binds to L-type calcium channels in vascular smooth muscle, inhibiting calcium entry and causing vasodilation.
Dosage
Standard Dosage
Adults:
A standard dose is typically 1 cm strip of cream (equivalent to 2.5-3 grams), applied inside and around the anus twice daily for up to three weeks. This delivers approximately 7.5 mg to 9 mg of nifedipine and 37.5 mg to 45 mg of lidocaine per application.
Children:
Use in children under 18 is generally not recommended, as safety and efficacy have not been established. Some sources mention the use in children over 12 years of age, however this information is not consistent.
Special Cases:
- Elderly Patients: Elderly patients should be closely monitored due to potential increased sensitivity to systemic effects, particularly from lidocaine. Dosage adjustments may be necessary.
- Patients with Renal Impairment: Caution is advised in patients with renal impairment. Dosage adjustments may be necessary depending on the severity of impairment.
- Patients with Hepatic Dysfunction: Similar to renal impairment, caution and potential dosage adjustments are necessary for patients with hepatic dysfunction, given the hepatic metabolism of both drugs.
- Patients with Comorbid Conditions: Use with caution in patients with heart disease, low blood pressure, bleeding disorders or methemoglobinemia.
Clinical Use Cases
Lidocaine + Nifedipine cream is specifically indicated for chronic anal fissures. Its use in other clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations is not established.
Dosage Adjustments
Dose modifications should be considered for patients with renal or hepatic dysfunction, based on the degree of impairment. Patients with cardiovascular disease or other relevant comorbidities should also be carefully monitored, and dosage adjustments may be necessary.
Side Effects
Common Side Effects:
- Burning or stinging sensation at the application site
- Itching, redness, or irritation around the anus
- Dizziness
- Headache
Rare but Serious Side Effects:
- Severe allergic reactions (rash, swelling, difficulty breathing)
- Severe dizziness or fainting
- Fast/pounding heartbeat
- Methemoglobinemia (pale, gray, or blue skin, shortness of breath, weakness, confusion, headache)
Long-Term Effects:
Limited data are available on long-term effects, but prolonged use could potentially lead to local skin reactions or systemic effects related to lidocaine or nifedipine if significant absorption occurs.
Adverse Drug Reactions (ADR):
Clinically significant ADRs include severe allergic reactions, methemoglobinemia, and severe hypotension. These require immediate medical attention.
Contraindications
- Hypersensitivity to lidocaine, nifedipine, or any component of the formulation
- Severe hypotension
- Cardiac insufficiency/heart failure
- Recent myocardial infarction
- Unstable angina
- Cardiovascular shock
- Congenital or idiopathic methemoglobinemia
- Glucose-6-phosphate dehydrogenase deficiency
- Pregnancy and breastfeeding
Drug Interactions
- Other lidocaine products (additive systemic effects)
- Class I antiarrhythmic medications (e.g., tocainide, mexiletine - additive cardiac effects)
- Beta-blockers (additive hypotensive effects)
- CYP3A4 inhibitors (e.g., cimetidine, erythromycin, grapefruit juice) or inducers (e.g., rifampicin, phenytoin) may alter the metabolism of nifedipine and lidocaine.
- Other blood pressure medications (additive hypotensive effects)
Pregnancy and Breastfeeding
This medication is contraindicated during pregnancy and breastfeeding due to the potential for fetal/neonatal exposure and adverse effects. Both lidocaine and nifedipine are excreted in breast milk.
Drug Profile Summary
- Mechanism of Action: Lidocaine: local anesthetic blocking sodium channels. Nifedipine: calcium channel blocker causing vasodilation and reducing muscle spasm.
- Side Effects: Common: local irritation, dizziness, headache. Serious: allergic reactions, methemoglobinemia, hypotension.
- Contraindications: Hypersensitivity, severe hypotension, heart failure, recent MI, unstable angina, pregnancy, breastfeeding.
- Drug Interactions: Other lidocaine products, Class I antiarrhythmics, beta-blockers, CYP3A4 inhibitors/inducers, other antihypertensives.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Adults: 1 cm strip applied rectally twice daily for up to 3 weeks. Children: Not recommended.
- Monitoring Parameters: Blood pressure, heart rate, signs of methemoglobinemia, local skin reactions.
Popular Combinations
Lidocaine and nifedipine are typically used in combination specifically for anal fissures. No other clinically significant combinations are routinely used.
Precautions
- General Precautions: Assess for allergies, medical history (especially heart, liver, and kidney conditions), and concomitant medications.
- Specific Populations: Contraindicated in pregnant and breastfeeding women. Use with caution in the elderly and those with organ dysfunction.
- Lifestyle Considerations: Avoid driving or operating machinery if dizziness occurs. Dietary recommendations (high-fiber diet) may be beneficial for anal fissure management.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Lidocaine + Nifedipine?
A: For adults, the typical dose is 1 cm of cream applied rectally twice daily for up to three weeks. Pediatric use is generally not recommended.
Q2: What are the common side effects?
A: Common side effects include local irritation (burning, stinging, itching), dizziness, and headache.
Q3: What are the serious side effects?
A: Serious side effects include allergic reactions, methemoglobinemia, and severe hypotension.
Q4: Can pregnant women use Lidocaine + Nifedipine cream?
A: No, it’s contraindicated during pregnancy and breastfeeding.
Q5: What are the drug interactions to be aware of?
A: Significant interactions may occur with other lidocaine products, Class I antiarrhythmics, beta-blockers, and CYP3A4 modulators. It’s crucial to assess for potential interactions with other medications the patient may be taking.
Q6: How does Lidocaine + Nifedipine cream work for anal fissures?
A: Lidocaine provides local pain relief, while nifedipine relaxes the anal sphincter and improves blood flow, promoting healing.
Q7: Are there any specific dietary recommendations when using this cream?
A: A high-fiber diet is often recommended to help soften stools and prevent further irritation of the anal fissure.
Q8: How should I counsel patients on applying the cream?
A: Advise patients to wash their hands thoroughly before and after application. The cream should be applied using the provided applicator or a gloved finger, directly into the anal canal and surrounding area.
Q9: What should patients do if they miss a dose?
A: If a dose is missed, apply it as soon as remembered, unless it is close to the next scheduled dose. Do not double the dose.
Q10: How should this medication be stored?
A: Store at room temperature, away from light and moisture. Keep the tube tightly closed when not in use. Keep out of reach of children.
