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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Wen Tong Gao
Generic Name
L-menthol
Active Ingredient
LevomentholCategory
Non-Standardized Plant Allergenic Extract [EPC]
Variants
1
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| 15 g/100g | OINTMENT | TOPICAL | 85954-003 |
Detailed information about Wen Tong Gao
References used for this content
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Wen Tong Gao, you must consult a qualified healthcare professional.
Levomenthol is a naturally occurring or synthetic compound belonging to the class of Non-Standardized Plant Allergenic Extracts. It is primarily utilized as a topical analgesic and antitussive for the temporary relief of minor aches, pains, and cough symptoms.
Dosage for Levomenthol varies significantly based on the route of administration and the condition being treated. For topical application, healthcare providers typically recommend applying a thin layer of the medication to the affected area no more than 3 to 4 times daily. Concentrations in these products can range from 1.25% to 16%. If using a transdermal patch, usually one patch is applied to the painful site for up to 8 or 12 hours, depending on the specific product labeling.
For antitussive (cough) purposes, oral lozenges containing Levomenthol are generally used by dissolving one lozenge slowly in the mouth every 2 hours as needed. It is critical not to exceed the maximum daily limit specified on the product packaging, as excessive menthol intake can lead to mucosal irritation or systemic effects.
Levomenthol must be used with extreme caution in the pediatric population. For children aged 2 to 12 years, topical application should be supervised by an adult and limited to lower concentrations (typically below 5%). For cough lozenges, the standard age for safe use is generally 6 years and older, though some products may be labeled for children as young as 2.
CRITICAL WARNING: Levomenthol-containing products (especially ointments) should NEVER be applied to the nostrils or face of infants or small children. There is a documented risk of laryngospasm (sudden constriction of the vocal cords) and respiratory distress in infants exposed to menthol vapors near the airway.
Systemic absorption of topical Levomenthol is generally low; therefore, dose adjustments for renal impairment are typically not required for standard topical use. However, for oral formulations or high-dose transdermal therapy, patients with severe renal disease should consult their physician, as the excretion of glucuronide metabolites may be delayed.
Since Levomenthol is metabolized by the liver, individuals with significant hepatic dysfunction (e.g., cirrhosis) should use Levomenthol products cautiously. Reduced metabolic capacity could theoretically lead to higher systemic levels, though this is rarely clinically significant with topical use.
No specific dosage adjustments are generally required for the elderly. However, older patients often have thinner, more fragile skin, which may increase the rate of absorption and the risk of localized skin irritation. Healthcare providers suggest starting with the lowest effective concentration.
If you miss a dose of Levomenthol, apply or take it as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and return to your regular schedule. Do not double the dose or apply more than the recommended amount to "make up" for a missed application.
Signs of a Levomenthol overdose, particularly through ingestion, include severe abdominal pain, nausea, vomiting, dizziness, staggering gait (ataxia), drowsiness, and in extreme cases, seizures or coma. If a topical product is swallowed or if an excessive amount is applied to the skin of a child, 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 frequency of use without medical guidance, as even over-the-counter products can cause adverse effects if misused.
Levomenthol is generally well-tolerated when used as directed, but because it works by stimulating sensory receptors, certain sensations are expected. Common side effects include:
> Warning: Stop taking Levomenthol and call your doctor immediately if you experience any of these serious adverse events:
Prolonged use of Levomenthol on the same skin area can lead to chronic skin irritation or a localized "rebound" effect where the underlying pain feels more intense once the cooling sensation wears off. There is also the potential for developing a sensitized allergic state, where the patient becomes increasingly reactive to any products containing menthol or peppermint oil. Chronic oral use of high-dose menthol may lead to irritation of the gastrointestinal lining or esophageal reflux (heartburn) due to the relaxation of the lower esophageal sphincter.
No FDA black box warnings currently exist for Levomenthol. However, the FDA has issued several drug safety communications regarding the risk of serious skin burns associated with certain over-the-counter topical muscle and joint pain relievers containing menthol. These reports highlight that while rare, the potential for permanent scarring exists if the product is misused (e.g., applied to broken skin or used with heating pads).
Report any unusual symptoms or persistent irritation to your healthcare provider. Monitoring the skin's response during the first few applications is highly recommended to ensure no hypersensitivity exists.
Levomenthol is intended for external use only (unless in the form of an oral lozenge or specifically formulated internal medication). It should never be ingested in its pure form or as a high-concentration topical oil. Patients must be educated that "natural" does not mean "harmless." Levomenthol is a potent bioactive compound that can cause significant toxicity if misused. Always keep Levomenthol-containing products out of the reach of children and pets, as small amounts can be toxic to animals and infants.
No FDA black box warnings for Levomenthol. However, users should heed all "Drug Facts" label warnings, particularly regarding the avoidance of heat and bandages.
For standard over-the-counter use, routine lab tests are not required. However, if a healthcare provider prescribes high-dose Levomenthol for chronic conditions, they may monitor:
Levomenthol does not typically cause sedation or cognitive impairment when used topically or in standard oral doses. However, if systemic toxicity occurs (overdose), symptoms like dizziness and ataxia can significantly impair the ability to drive or operate heavy machinery safely.
There are no direct contraindications between topical Levomenthol and moderate alcohol consumption. However, alcohol can cause vasodilation (widening of blood vessels), which might increase the absorption of topical menthol or exacerbate the "burning" sensation. For oral menthol, alcohol may increase the risk of gastric irritation.
Levomenthol does not require a tapering period. You may stop using it at any time. However, if you are using it to manage chronic pain and stop suddenly, your original symptoms may return. If you experience a worsening of symptoms upon discontinuation, consult your healthcare provider to discuss alternative pain management strategies.
> Important: Discuss all your medical conditions, including any history of skin sensitivities or respiratory issues, with your healthcare provider before starting Levomenthol.
While Levomenthol has few absolute contraindications with other drugs, it should never be used simultaneously on the same area of skin with other topical irritants or medicated creams (such as capsaicin or topical NSAIDs) unless specifically directed by a doctor. Combining these can lead to severe skin irritation, blistering, or unpredictable absorption rates of the other medications.
Levomenthol is not known to significantly interfere with common blood or urine laboratory tests. However, its presence in the urine (as a glucuronide) may occasionally interfere with specific specialized toxicology screenings that use gas chromatography-mass spectrometry, potentially causing unidentified peaks.
For each major interaction, the primary concern is either increased toxicity (due to enhanced skin penetration) or reduced efficacy (due to pH changes in the stomach for oral forms). Management usually involves spacing doses or avoiding concurrent application to the same skin site.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, especially if you use other topical treatments or are on blood-thinning therapy.
Levomenthol must NEVER be used in the following circumstances:
These conditions require a careful risk-benefit analysis by a healthcare professional:
Patients who are allergic to other members of the Lamiaceae (mint) family—including basil, oregano, rosemary, sage, and thyme—should use Levomenthol with caution, as cross-reactivity is possible. Additionally, those sensitive to Standardized Chemical Allergens such as carvone or limonene may also react to Levomenthol.
> Important: Your healthcare provider will evaluate your complete medical history, including any history of gallbladder disease or respiratory sensitivities, before prescribing or recommending Levomenthol.
Levomenthol is generally considered safe for topical use during pregnancy when applied to small areas for short durations. It is often classified as FDA Pregnancy Category C (under the old system), meaning animal studies have shown an adverse effect but there are no adequate studies in humans, or no studies have been conducted.
Levomenthol is known to be excreted into breast milk in small amounts when taken orally. When used topically, the amount reaching the milk is likely negligible.
As established, Levomenthol is contraindicated in children under 2 years of age. For older children, it is used for cough and minor muscle pain.
In the elderly, the primary concerns are skin integrity and polypharmacy.
Patients with end-stage renal disease (ESRD) or those on dialysis do not typically require dose adjustments for topical Levomenthol. However, they should be monitored for any unusual systemic symptoms, as the clearance of the glucuronide metabolite may be impaired. Oral use should be approached with caution.
In patients with Child-Pugh Class B or C hepatic impairment, the metabolism of Levomenthol may be significantly slowed. While topical use is generally safe, healthcare providers should monitor these patients for signs of menthol toxicity, such as increased lethargy or dizziness.
> Important: Special populations require individualized medical assessment to ensure that the benefits of Levomenthol therapy outweigh the potential risks unique to their physiological state.
Levomenthol acts as a selective activator of the Transient Receptor Potential Melastatin 8 (TRPM8) channel. This cold-sensing transmembrane protein is found on primary afferent neurons (sensory nerves). When Levomenthol binds to the TRPM8 channel, it lowers the threshold for activation, allowing the channel to open at normal skin temperatures. This results in an influx of cations ($Na^+$, $Ca^{2+}$), leading to a sensation of cold.
Additionally, Levomenthol provides analgesia through several other pathways:
| Parameter | Value |
|---|---|
| Bioavailability | High (Oral); Low to Moderate (Topical) |
| Protein Binding | ~25% to 30% |
| Half-life | 3 - 6 hours |
| Tmax | 1 - 2 hours (Oral); Variable (Topical) |
| Metabolism | Hepatic (Hydroxylation & Glucuronidation) |
| Excretion | Renal (>90% as metabolites) |
Levomenthol is a terpenoid and a secondary alcohol. In a clinical setting, it is classified as a Counter-irritant and a Topical Analgesic. It shares some functional characteristics with other TRP channel agonists like capsaicin (which targets TRPV1, the heat receptor), though its sensory profile is the opposite.
Common questions about Wen Tong Gao
Levomenthol is primarily used as a topical pain reliever and a cough suppressant. When applied to the skin in creams or patches, it provides a cooling sensation that helps distract the brain from deeper muscle and joint pain, such as that caused by arthritis or backaches. In the form of oral lozenges, it works by soothing the throat and stimulating 'cold' receptors in the respiratory tract, which helps suppress the urge to cough. Some healthcare providers also recommend specific oral formulations for the relief of Irritable Bowel Syndrome (IBS) symptoms. It is a versatile ingredient found in many over-the-counter products for minor cold and pain relief.
The most common side effects of Levomenthol are localized to the area where the product is applied. These include a strong sensation of coldness, mild burning, or stinging, which are usually temporary and part of the drug's mechanism of action. Some users may also notice mild skin redness or dryness at the application site. If used in lozenge form, a temporary tingling or numbing sensation in the mouth is common. Most of these effects resolve quickly once the product is no longer in contact with the skin or mucous membranes. However, if you experience severe blistering or persistent itching, you should discontinue use and consult a doctor.
There is no known direct interaction between topical Levomenthol and alcohol consumption. However, alcohol can cause blood vessels to dilate, which might increase the absorption of menthol through the skin or make the cooling/burning sensation feel more intense. If you are taking oral Levomenthol preparations, such as peppermint oil capsules, alcohol may increase the risk of stomach irritation or acid reflux. It is generally best to use these products in moderation if you are also consuming alcohol. Always check with your healthcare provider if you have concerns about how alcohol might affect your specific treatment plan.
Levomenthol is generally considered safe for topical use during pregnancy when applied to small areas of the body for short periods. There is no evidence that the small amount absorbed through the skin reaches the developing fetus in harmful quantities. However, pregnant women should avoid applying high-concentration menthol products to large areas of the body or using them for extended periods without medical advice. Oral ingestion of menthol in high doses is not recommended during pregnancy due to a lack of comprehensive safety studies. Always consult your obstetrician before starting any new medication, even over-the-counter topical treatments, while pregnant.
The onset of action for Levomenthol is quite rapid. When applied topically as a gel or spray, most patients begin to feel the cooling sensation and associated pain relief within 1 to 5 minutes. For oral lozenges, the soothing effect on the throat and the antitussive (cough-suppressing) action usually begin as soon as the lozenge starts to dissolve in the mouth. Transdermal patches may take slightly longer—about 15 to 30 minutes—to reach their full effect, but they provide a much longer duration of relief. If you do not feel any relief within 7 days of regular use, you should contact your healthcare provider to investigate the underlying cause of your symptoms.
Yes, you can stop using Levomenthol suddenly without experiencing physical withdrawal symptoms, as it is not an addictive substance. Unlike some prescription pain medications, Levomenthol does not require a tapering schedule. However, if you were using it to manage a chronic condition like arthritis, your pain and symptoms may return once the medication is stopped. If you find that your symptoms worsen significantly after you stop using the product, it is important to discuss other long-term management options with your doctor. There are no known 'rebound' effects associated with the occasional use of menthol for cough or minor pain.
If you miss a dose of Levomenthol, simply apply or take it as soon as you remember. If it is almost time for your next scheduled application or lozenge, skip the missed dose and continue with your regular routine. Do not apply a double amount of cream or take two lozenges at once to make up for the missed dose, as this increases the risk of skin irritation or systemic side effects. Because Levomenthol is often used on an 'as-needed' basis for symptom relief, missing a single dose is generally not a cause for concern. Consistency is most important when using it for chronic conditions as directed by a physician.
There is no scientific evidence to suggest that Levomenthol causes weight gain. Whether used topically or orally, menthol does not affect the metabolic processes or hormonal balances that typically lead to changes in body weight. It is a non-caloric compound and does not influence appetite in a way that would lead to increased food intake. If you notice unexpected weight gain while using a product containing Levomenthol, it is likely due to other factors, such as changes in activity level due to your underlying pain, or other medications you may be taking. You should discuss any significant weight changes with your healthcare provider.
Levomenthol can be used alongside most systemic medications, but caution is needed with other topical treatments. You should not apply Levomenthol to the same area of skin where you have recently applied another medicated cream, such as a steroid or a topical NSAID, as menthol can increase the absorption of these drugs and potentially cause side effects. If you are taking oral blood thinners like warfarin, you should consult your doctor before using high-dose oral menthol, as there may be a slight risk of interaction. Always provide your healthcare provider with a full list of your current medications to ensure there are no specific concerns.
Yes, Levomenthol is widely available as a generic product and is an active ingredient in hundreds of different over-the-counter brands. You can find it in generic muscle rubs, cough drops, and anti-itch creams. Generic versions are required by the FDA to have the same quality and strength as brand-name products. Because it is a naturally derived compound that has been used in medicine for a long time, it is very affordable and accessible. When purchasing a generic version, simply check the 'Active Ingredients' section of the Drug Facts label to ensure it contains the correct percentage of menthol for your needs.
Other drugs with the same active ingredient (Levomenthol)