Usage
Cetrimide + Permethrin is primarily prescribed for the treatment of scabies and head lice infestations. It can also be used for other skin infections or infestations, as determined by a doctor. Cetrimide is an antiseptic and Permethrin is classified as a pyrethroid insecticide and scabicide. The combination works by disrupting the cell membranes of bacteria and other microorganisms (Cetrimide’s action), which helps prevent secondary skin infections. Permethrin interferes with the nervous system of parasites like scabies mites and lice, causing paralysis and death.
Alternate Names
While “Cetrimide + Permethrin” is the standard generic name, some brand names include “Scabgen-C”, “Permedin C”, and “Lixofer C”. Other names may exist regionally.
How It Works
Pharmacodynamics: Cetrimide acts as a cationic surfactant, disrupting the cell membranes of bacteria and fungi. Permethrin interferes with sodium channels in the nerve cells of parasites, leading to their paralysis and death.
Pharmacokinetics: Cetrimide, when applied topically, has limited systemic absorption. Permethrin, also applied topically, is poorly absorbed through the skin. The absorbed portion is rapidly metabolized and excreted, primarily through the kidneys.
Mode of Action: Cetrimide disrupts the cell membranes of microbes. Permethrin targets the parasite’s nervous system by delaying the closure of sodium channels in nerve cell membranes. This prolonged sodium influx causes repetitive nerve firing and eventual paralysis.
Elimination: The small amount of permethrin that is absorbed systemically is rapidly metabolized and excreted primarily via the kidneys.
Dosage
Standard Dosage
Adults: Apply a thin layer of 5% permethrin cream to the entire body from the neck down, including the soles of the feet and between fingers and toes. Leave on for 8-14 hours, then wash off thoroughly. A single application is usually sufficient, but a second application may be necessary after 7 days if live mites are still present. For head lice, apply 1% permethrin lotion or cream rinse to washed, towel-dried hair. Leave on for 10 minutes, then rinse and comb out nits. Repeat after 7 days if needed.
Children: For scabies in children 2 months and older, follow adult instructions. For children younger than 2 months, consult a doctor. For head lice, use 1% permethrin lotion/cream rinse as directed for adults. Supervise application in children.
Special Cases:
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Elderly Patients: Follow adult dosage. In addition, apply to the scalp, hairline, forehead, temples, and ears for scabies.
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Patients with Renal Impairment: No dose adjustment is typically necessary for topical application. However, caution should be exercised.
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Patients with Hepatic Dysfunction: No dose adjustment is typically necessary for topical application. However, caution should be exercised.
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Patients with Comorbid Conditions: Consider pre-existing skin conditions such as eczema or psoriasis, as permethrin might exacerbate these.
Clinical Use Cases The primary clinical use cases are scabies and head lice infestations. Use in intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations is not relevant for this medication.
Dosage Adjustments
Dose adjustments are primarily based on age and body surface area. Always follow product-specific instructions. For patients with pre-existing skin conditions or other comorbidities, careful assessment is required, and a physician should be consulted.
Side Effects
Common Side Effects:
Itching, burning, stinging, tingling, redness, or rash at the application site. Dry skin may also occur.
Rare but Serious Side Effects: Allergic reactions (e.g., difficulty breathing, swelling of the face, lips, tongue, or throat). Seizures (rare, primarily with misuse or overdose).
Long-Term Effects: No significant long-term adverse effects are typically associated with proper use of this medication.
Contraindications
Hypersensitivity to permethrin, cetrimide, pyrethrins, chrysanthemums, or any component of the formulation. Infants under 2 months of age for over-the-counter formulations. Premature infants. Patients with uncontrolled seizure disorders.
Drug Interactions
No significant drug interactions have been reported with topical application of Cetrimide + Permethrin. However, inform your doctor about all medications, supplements, and herbal products you are using.
Pregnancy and Breastfeeding
Consult a physician before using during pregnancy or breastfeeding. Safety during these periods has not been definitively established, although topical permethrin is considered low risk.
Drug Profile Summary
- Mechanism of Action: Cetrimide disrupts microbial cell membranes. Permethrin interferes with parasite nerve function.
- Side Effects: Itching, burning, stinging, redness, rash. Rarely, allergic reactions or seizures.
- Contraindications: Hypersensitivity, infants under 2 months (OTC), premature infants, uncontrolled seizures.
- Drug Interactions: None well documented.
- Pregnancy & Breastfeeding: Consult a doctor.
- Dosage: See “Dosage” section.
- Monitoring Parameters: Observe the application site for skin reactions and treatment efficacy.
Popular Combinations
The combination of Cetrimide and Permethrin is itself a common formulation.
Precautions
- General Precautions: Pre-screening for allergies and underlying skin conditions.
- Specific Populations: Consult a physician for use in pregnant/breastfeeding women and infants.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cetrimide + Permethrin?
A: See “Dosage” section for detailed information.
Q2: How should Cetrimide + Permethrin be applied?
A: Apply a thin layer to clean, dry, cool skin. For scabies, apply to the entire body. For head lice, apply to washed and towel-dried hair.
Q3: How long should Cetrimide + Permethrin be left on the skin?
A: For scabies, leave the cream on for 8-14 hours. For head lice, leave the lotion/rinse on for 10 minutes.
Q4: How often should Cetrimide + Permethrin be applied?
A: A single application is usually sufficient. A second application may be needed after 7 days for scabies or head lice if live mites/lice are still present.
Q5: Can Cetrimide + Permethrin be used on infants?
A: For over-the-counter formulations, do not use on infants under 2 months. Consult a physician for infants younger than 2 months.
Q6: What should I do if Cetrimide + Permethrin gets in my eyes?
A: Immediately flush the eyes with plenty of water.
Q7: Can Cetrimide + Permethrin be used during pregnancy or breastfeeding?
A: Consult a physician before using during pregnancy or breastfeeding.
Q8: What are the common side effects of Cetrimide + Permethrin?
A: Common side effects include itching, burning, stinging, redness, and rash at the application site.
Q9: What are the signs of an allergic reaction to Cetrimide + Permethrin?
A: Signs of an allergic reaction include difficulty breathing, hives, and swelling of the face, lips, tongue, or throat. Seek immediate medical attention if these occur.
