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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Good Sense Lice Killing Creme Rinse
Generic Name
Permethrin
Active Ingredient
PermethrinCategory
Pyrethroid [EPC]
Variants
1
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| 1 mg/100mL | LOTION | TOPICAL | 0113-1910 |
Detailed information about Good Sense Lice Killing Creme Rinse
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Good Sense Lice Killing Creme Rinse, you must consult a qualified healthcare professional.
Permethrin is a synthetic pyrethroid used topically to treat infestations of scabies and head lice. It works by disrupting the nervous system of parasites, leading to paralysis and death.
For the treatment of scabies in adults, the standard protocol involves the application of Permethrin 5% cream. A single application is usually sufficient to clear the infestation, although a second application 7 to 14 days later is often recommended to ensure any newly hatched mites are destroyed. Adults typically require approximately 30 grams (one full tube) to cover the entire body from the neck down to the soles of the feet.
For head lice, adults should use Permethrin 1% lotion. After washing the hair with a regular shampoo (without conditioner) and towel-drying it, a sufficient amount of the lotion should be applied to saturate the hair and scalp, especially behind the ears and at the nape of the neck. The product is left in place for 10 minutes and then rinsed thoroughly with warm water.
Permethrin is generally considered safe for children, but the dosage must be carefully managed based on age.
Because systemic absorption of topical permethrin is less than 2%, dose adjustments for patients with kidney disease are generally not required. The kidneys process the inactive metabolites, and the low concentrations do not typically pose a risk of accumulation.
Similar to renal impairment, the minimal systemic absorption means that dose adjustments for liver disease are usually unnecessary. However, patients with severe hepatic failure should be monitored for any unusual systemic reactions.
Elderly patients can use standard dosages. However, healthcare providers may advise caution if the patient has very thin or fragile skin, as this could theoretically increase the amount of drug absorbed into the bloodstream.
Permethrin is for external use only. It should never be swallowed or applied to mucous membranes.
Since permethrin is usually a one-time or two-time application, a "missed dose" is rare. If you forget to apply it at the scheduled time, apply it as soon as you remember. If you were supposed to apply a second treatment a week later and forgot, apply it as soon as possible to ensure the life cycle of the parasite is broken.
Signs of a topical overdose are rare but may include severe skin irritation, swelling, or redness. If the medication is accidentally swallowed, symptoms may include nausea, vomiting, dizziness, and abdominal pain. In the event of accidental ingestion, contact a Poison Control Center or seek emergency medical attention immediately.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose or re-apply the medication more frequently than directed, as this increases the risk of skin irritation without improving the cure rate.
The most frequently reported side effects of permethrin are localized to the site of application. Because the drug is used to treat conditions that are inherently itchy, it can be difficult to distinguish between the symptoms of the infestation and the side effects of the medication.
> Warning: Stop using Permethrin and call your doctor immediately if you experience any of these serious reactions.
Permethrin is not intended for long-term or chronic use. However, repeated, unnecessary applications can lead to:
No FDA black box warnings for Permethrin. It is generally recognized as safe when used as directed for its narrow range of indications.
Report any unusual symptoms or persistent skin changes to your healthcare provider. If the itching does not resolve within four weeks of treatment, a follow-up with a dermatologist is necessary to confirm the mites have been eradicated.
Permethrin is intended for topical use only. It is a powerful chemical that must be handled with care. Patients should ensure that the medication does not come into contact with the eyes, nose, mouth, or vagina. If contact occurs, the area should be flushed immediately with large amounts of water. Additionally, permethrin is highly toxic to certain household pets, particularly cats. Cats lack the liver enzyme (glucuronosyltransferase) required to metabolize permethrin; contact with even small amounts of the 5% cream can be fatal to a cat. If you have cats, keep them away from treated individuals until the medication has been washed off.
No FDA black box warnings for Permethrin. The safety profile is well-established for the approved indications of lice and scabies treatment in both adults and children over two months of age.
There are no standard laboratory tests (like blood counts or liver panels) required for the use of permethrin due to its low systemic absorption. However, clinical monitoring is essential:
Permethrin does not typically affect the ability to drive or operate heavy machinery. Because systemic levels are so low, it does not cause drowsiness or impairment of motor skills.
There are no known direct interactions between topical permethrin and alcohol consumption. However, alcohol can cause vasodilation (widening of blood vessels), which might theoretically increase skin sensitivity or itching during treatment.
Permethrin is used as a short-term pulse therapy. There are no withdrawal syndromes associated with stopping its use. If treatment is discontinued before the parasites are fully eradicated, the infestation will likely return and may spread to other household members.
> Important: Discuss all your medical conditions, especially any history of skin sensitivity or respiratory issues, with your healthcare provider before starting Permethrin.
There are no documented "never-use" drug combinations for topical permethrin due to its minimal systemic absorption. However, it should not be used simultaneously with other topical scabicides or pediculicides (such as lindane or malathion) unless specifically instructed by a specialist, as this can lead to severe skin toxicity and irritation without increasing the efficacy of the treatment.
There are no known food interactions with topical permethrin. Unlike oral medications, the absorption of permethrin is not affected by the consumption of grapefruit, dairy, or high-fat meals.
There are no documented interactions between topical permethrin and common herbal supplements like St. John's Wort or Ginkgo Biloba. Because the drug does not significantly enter the bloodstream, it does not interact with the hepatic enzymes that typically cause supplement-drug interactions.
Permethrin does not interfere with standard blood or urine laboratory tests. It does not cause false positives on drug screenings or affect glucose, cholesterol, or electrolyte readings.
Most interactions with permethrin are pharmacodynamic in nature, meaning they occur at the site of action (the skin). For example, the interaction with corticosteroids is pharmacodynamic because the steroid changes the body's immune response to the parasite, not the concentration of the permethrin itself. Pharmacokinetic interactions (changes in how the body processes the drug) are rare and would only occur if the skin barrier is so compromised that systemic absorption reaches levels high enough to interact with liver enzymes.
To minimize interaction risks:
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, even if they are only applied to the skin.
There are several conditions where permethrin must NEVER be used because the risks far outweigh any potential benefits:
These are conditions that require a careful risk-benefit analysis by a healthcare provider:
Cross-sensitivity occurs when the immune system reacts to a drug because it is chemically similar to another substance the person is allergic to. For permethrin, cross-sensitivity is most common with:
> Important: Your healthcare provider will evaluate your complete medical history and allergy profile before prescribing Permethrin to ensure it is safe for you.
Permethrin is classified as FDA Pregnancy Category B. This means that animal reproduction studies have failed to demonstrate a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women. Because systemic absorption is so low (less than 2%), the amount of drug that could potentially reach the developing fetus is considered negligible. Most clinical guidelines suggest that permethrin is the preferred treatment for scabies during pregnancy when treatment is necessary. However, it should only be used under the direction of a physician, particularly during the first trimester.
It is not known whether permethrin is excreted in human breast milk. However, because systemic levels in the mother's blood are extremely low, the amount that could pass into milk is likely insignificant. The primary concern during breastfeeding is the infant's direct skin contact with the treated areas of the mother's body. If the mother is being treated for scabies, she should thoroughly wash the cream off her breasts before nursing to prevent the infant from ingesting the medication or having it touch their sensitive skin.
Permethrin is widely used in children. For head lice, it is approved for children as young as 2 months of age. For scabies, the 5% cream is also approved for infants 2 months and older. In pediatric patients, it is vital to prevent the child from licking the cream or getting it into their eyes. Parents are often advised to put mittens or socks on an infant's hands after application to prevent them from sucking on their fingers and ingesting the drug.
Clinical studies of permethrin did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious. The skin of older adults is often thinner and drier, which may lead to increased irritation. Furthermore, elderly patients in long-term care facilities are at higher risk for "crusted scabies" (Norwegian scabies), a severe form of the infestation that may require multiple treatments and oral medications in addition to permethrin.
No dosage adjustments are provided in the manufacturer's labeling for patients with renal impairment. The tiny fraction of the drug that is absorbed is converted into inactive metabolites before being cleared by the kidneys, making it safe for most patients with kidney disease.
No dosage adjustments are required for patients with liver disease. While the liver is responsible for metabolizing the small amount of absorbed permethrin, the total quantity is so low that even a compromised liver can typically process it without difficulty.
> Important: Special populations require individualized medical assessment. Always inform your doctor if you are pregnant, planning to become pregnant, or nursing before using this medication.
Permethrin is a neuronal sodium channel modulator. In parasites, it acts on the nerve cell membranes to disrupt the sodium channel current by which the polarization of the membrane is regulated. Specifically, it binds to the alpha-subunit of the voltage-gated sodium channels. By delaying the closing (inactivation) of these channels, permethrin causes a state of hyperexcitability in the parasite's nervous system. This results in spontaneous firing of neurons, followed by muscular tetany (sustained contraction) and eventual functional paralysis. Because the respiratory muscles of the lice or mites are affected, the parasites die of asphyxiation or exhaustion.
The pharmacodynamic effect of permethrin is rapid, often referred to as the "knockdown effect." Upon contact with the 1% or 5% concentration, the parasite's movement is inhibited within minutes. However, the drug is primarily a killing agent (pediculicidal/scabicidal) rather than an egg-killing agent (ovicidal). While it may kill some eggs, many eggs remain viable, which is why a second application is often required to kill the nymphs that hatch after the first treatment. There is no evidence of the development of tolerance within a single treatment course, though genetic resistance in lice populations is a growing global concern.
| Parameter | Value |
|---|---|
| Bioavailability | < 2% (Topical) |
| Protein Binding | Highly bound in plasma (though systemic levels are negligible) |
| Half-life | 8-12 hours (Skin clearance) |
| Tmax | Not applicable (Topical) |
| Metabolism | Hepatic ester hydrolysis to inactive metabolites |
| Excretion | Renal (>90% of absorbed dose) |
Permethrin is a synthetic pyrethroid. It is categorized as an ectoparasiticide. Related medications in this class include pyrethrins (the natural version) and other synthetic variants like phenothrin, though permethrin remains the most widely used in clinical medicine.
Common questions about Good Sense Lice Killing Creme Rinse
Permethrin is primarily used to treat infestations of the skin and hair caused by parasites. The 5% cream formulation is the standard prescription treatment for scabies, a condition where tiny mites burrow under the skin. The 1% lotion or liquid formulation is a common over-the-counter and prescription treatment for head lice. It works by paralyzing and killing the parasites on contact. Occasionally, healthcare providers may use it off-label for other types of lice or skin-dwelling mites.
The most common side effects are localized skin reactions at the site where the medication was applied. Patients frequently report itching, which may actually feel worse for a short time after the cream is applied. Other common reactions include mild skin redness, a stinging or burning sensation, and occasionally a mild rash. These symptoms are usually temporary and resolve once the medication is washed off. If you experience severe swelling or a worsening rash, you should contact your doctor.
There are no known direct chemical interactions between topical permethrin and alcohol. Since the medication is applied to the skin and very little enters the bloodstream, alcohol does not interfere with how the drug works. However, alcohol can cause the blood vessels in the skin to dilate, which might increase skin sensitivity or make the itching from scabies feel more intense. It is generally safe, but moderation is advised to avoid aggravating skin discomfort. Always consult your doctor for personalized advice.
Permethrin is classified as a Pregnancy Category B medication, meaning it is generally considered safe for use when necessary. Animal studies have shown no harm to the fetus, and because less than 2% of the drug is absorbed through the mother's skin, the risk to the baby is very low. It is often the preferred treatment for scabies in pregnant women. However, it should only be used under the guidance of a healthcare provider. They will help weigh the benefits of treating the infestation against any theoretical risks.
Permethrin begins killing lice and mites almost immediately upon contact. For head lice, the treatment is usually left on for 10 minutes, which is sufficient to kill active lice. For scabies, the cream must remain on the skin for 8 to 14 hours to ensure all mites are exposed. While the parasites die quickly, the itching associated with the infestation can last for several weeks. This is because your body is still reacting to the dead mites and their waste products left under the skin.
Permethrin is not a daily medication, so there is no risk of withdrawal or "stopping suddenly" in the traditional sense. It is usually applied once or twice as a complete treatment course. However, if you do not complete the full application as directed (for example, washing it off too early), the parasites may not all be killed. This can lead to a failed treatment and a return of the infestation. Always follow the specific timing instructions provided by your pharmacist or doctor.
If you miss your scheduled application of permethrin, simply apply it as soon as you remember. If you were supposed to apply a second treatment 7 days after the first and you forgot, apply it as soon as possible. The second dose is important because it kills any new parasites that may have hatched from eggs after the first treatment. Missing the second dose increases the chance that the infestation will start all over again. Consistency with the two-dose schedule is key for a total cure.
No, permethrin does not cause weight gain. Weight gain is typically a side effect of systemic medications that affect metabolism, hormones, or appetite, such as oral steroids or certain antidepressants. Because permethrin is applied topically to the skin and has very minimal systemic absorption, it does not enter the body in high enough quantities to affect your weight. Any changes in weight while using permethrin are likely due to other factors or medications. If you have concerns about weight changes, discuss them with your healthcare provider.
Permethrin is generally safe to use alongside most oral medications because it stays on the surface of the skin. However, you should be cautious when using other topical products, such as medicated creams or strong skin cleansers, at the same time. Other topical products can interfere with permethrin's ability to reach the parasites or may increase skin irritation. It is best to apply permethrin to clean, dry skin that is free of other treatments. Always provide your doctor with a full list of all medications you use.
Yes, permethrin is widely available as a generic medication in both 1% and 5% concentrations. Generic versions are chemically identical to brand-name products like Elimite or Nix and are required by the FDA to meet the same standards for safety and efficacy. Using the generic version is usually much more cost-effective for patients. Whether you use a brand-name or generic version, the application instructions and potential side effects remain the same. Your pharmacist can help you identify the most affordable option.
Other drugs with the same active ingredient (Permethrin)