Lignocaine, also widely known as lidocaine, is a medication belonging to the amino amide class of drugs used to temporarily relieve pain. This substance functions as a local anesthetic by stabilizing the nerve cell membrane, which prevents the initiation and conduction of electrical impulses that signal pain. The gel formulation is specifically designed for topical application to the skin or mucous membranes to achieve localized numbness. Lignocaine achieves this by blocking the flow of sodium ions into nerve cells, silencing pain signals in the targeted area.
Therapeutic Applications of Lignocaine Gel
Lignocaine gel is frequently used to manage discomfort arising from minor skin irritations and certain common medical conditions. It provides temporary relief from pain and itching caused by issues such as sunburn, minor cuts, scrapes, and insect bites. The gel is also commonly applied to soothe the symptoms of skin conditions like eczema.
The medication plays a significant role in managing anorectal discomfort, offering temporary numbness for conditions such as hemorrhoids and anal fissures. The gel helps to reduce the pain and inflammation associated with the affected tissues. For internal use, the gel form is valued as an anesthetic lubricant for various clinical procedures.
Healthcare professionals utilize the gel to prepare patients for instrumentation of the urethra, such as during urinary catheterization or cystoscopy. It numbs the lining of the urethra to prevent pain during the insertion of instruments. Similarly, the gel is sometimes used to lubricate and anesthetize the nose, mouth, or throat before procedures like intubation.
The formulation’s ability to maximize contact with mucous membranes makes it effective for these applications. This localized numbing allows for a reduction in discomfort without affecting consciousness or sensation in the rest of the body. The concentration of the gel used depends on the site of application and the nature of the procedure.
Proper Application and Dosage Guidelines
Safe and effective use of lignocaine gel depends on following correct application techniques and adhering to dosage limits. For minor skin irritations, the affected area should be gently cleaned and dried before the gel is applied. A thin layer is typically spread over the painful or itchy skin.
When used for conditions like hemorrhoids or anal fissures, the gel should be applied directly to the external area as directed by a healthcare provider. For internal procedures, the gel is usually applied directly onto the medical instrument, such as a catheter, to serve as an anesthetic lubricant. The onset of the numbing effect is rapid, often beginning within three to five minutes of application.
Accurate measurement is important, especially when applying the gel over a large area or to sensitive mucous membranes. For adults using a 5% ointment for minor skin conditions, a single application should not exceed 5 grams (roughly six inches of ointment). Application frequency for minor skin pain is usually limited to three or four times per day.
For internal procedures using a 2% jelly, the maximum dose is often capped at 600 milligrams within any 12-hour period. Exceeding the recommended dosage or frequency significantly increases the risk of the drug being absorbed into the bloodstream. Patients should never use more than the prescribed amount.
Recognizing and Avoiding Systemic Toxicity
The primary safety concern with topical lignocaine gel is the risk of systemic absorption, known as Local Anesthetic Systemic Toxicity (LAST). This occurs when excessive amounts of the drug enter the bloodstream, which is more likely if the gel is applied to large areas, broken skin, or highly absorptive mucous membranes. To avoid this, the gel should never be applied to large, raw, or blistered areas of skin without medical guidance.
The initial signs of toxicity often involve the central nervous system (CNS) and can include lightheadedness, nervousness, or confusion. Patients may also experience auditory changes such as ringing in the ears (tinnitus), blurred vision, or a metallic taste in the mouth. As the systemic concentration increases, more severe symptoms like muscle twitching, tremors, or seizures can occur.
Cardiovascular effects are a serious sign of systemic toxicity and may present as a slowed heart rate (bradycardia), low blood pressure (hypotension), or irregular heart rhythms. Individuals with pre-existing heart, liver, or kidney disease, as well as the very young and the elderly, are at a higher risk for developing LAST.
If any signs of systemic toxicity appear, the use of the gel must be stopped immediately, and professional medical help should be sought. Prevention is achieved by strictly adhering to the maximum dosage and frequency guidelines provided by a healthcare provider or the product labeling. Applying the gel only to intact skin, or as directed for specific procedures, minimizes the potential for systemic absorption.