A topical combination formulation containing a local anesthetic (Lidocaine) and a calcium channel blocker (Nifedipine). It is primarily indicated for the treatment of chronic anal fissures and hemorrhoids, providing symptomatic relief from pain and spasm while promoting healing. The combination targets both neuropathic pain (via sodium channel blockade) and smooth muscle spasm of the internal anal sphincter (via calcium channel blockade).
Adult: Apply a pea-sized amount (approximately 0.5 to 1 gram) topically to the affected perianal area, 2-3 times daily, especially after bowel movements and at bedtime. Duration: Typically 6-8 weeks for chronic fissures.
Note: 1. Wash hands before and after application. 2. Clean and dry the perianal area gently. 3. Apply a thin layer externally to the anal verge and, if possible, gently apply a small amount just inside the anal canal using a finger cot or applicator. 4. Avoid deep insertion. 5. Do not use with occlusive dressings.
The combination works synergistically. Lidocaine blocks voltage-gated sodium channels in neuronal membranes, inhibiting the initiation and conduction of nerve impulses, thereby providing local anesthesia and pain relief. Nifedipine blocks L-type calcium channels in vascular and gastrointestinal smooth muscle cells, leading to a reduction in intracellular calcium. In the internal anal sphincter, this causes chemical sphincterotomy - reducing resting anal pressure and spasm, improving blood flow to the anal mucosa, and promoting healing of fissures.
Pregnancy: Category C (US FDA). Animal studies show adverse effects (teratogenicity, embryolethality with nifedipine). No adequate, well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus, typically reserved for severe, debilitating fissures.
Driving: May cause dizziness or blurred vision. Patients should not drive or operate machinery until they know how the medicine affects them.
| Beta-blockers (e.g., Propranolol, Atenolol) | Increased risk of hypotension, bradycardia, and heart failure. Potentiates negative inotropic effects. | Major |
| CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Erythromycin, Clarithromycin, Ritonavir) | Markedly increased systemic levels of Nifedipine, leading to severe hypotension and edema. | Major |
| Other Antiarrhythmics (e.g., Amiodarone) | Increased risk of cardiac arrhythmias with systemic Lidocaine. | Major |
| Other Local Anesthetics | Additive toxic effects if used concurrently on other body sites. | Moderate |
| Antihypertensives (Diuretics, ACE Inhibitors) | Additive hypotensive effect. | Moderate |
| CYP1A2 Inducers (e.g., Smoking) | May reduce Lidocaine efficacy. | Minor |
Same composition (Lidocaine (1.5% w/w) + Nifedipine (0.3% w/w)), different brands: