Locasten

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Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Locasten

Property Description
Active ingredient Clotrimazole
Form Cream, solution, vaginal tablet
Pharmacological class Azole Antifungal Agent
Common use Addressing fungal and yeast infections
Origin Synthetic (Imidazole derivative)

What Type of Medicine is Locasten?

Locasten is the trade preparation for the antifungal agent Clotrimazole, functioning as a targeted medication against fungal pathogens. Clotrimazole is classified chemically as an imidazole derivative and belongs to the wider Azole antifungals class. This classification is important because the entire group is clinically recognized for its specific mode of action against fungal cell structures.

Locasten is a monoseptic medicine, which means it relies solely on the power of the Clotrimazole compound. It is designed to address a problem caused by living microorganisms and is typically used for localized fungal issues, such as those affecting the skin or mucosal membranes.

Composition, Origin, and Available Forms

The composition of Locasten is centered on the active ingredient Clotrimazole, a reliably manufactured synthetic compound. Clotrimazole exhibits broad-spectrum antimycotic activity.

The drug is delivered in several specialized dosage forms tailored for localized treatment, including a cream, a solution, and a vaginal tablet. The availability of these distinct pharmaceutical preparations allows for two primary routes of administration: topical application onto the skin or intravaginal insertion. This range of forms is a differentiating factor, allowing precise delivery of the active ingredient directly to the affected area.

The General Purpose of Locasten

The general purpose of Locasten is to act as a broad-spectrum antifungal to eliminate the microorganisms causing infection. This therapeutic role is achieved because Clotrimazole interferes with a process vital to the fungal cell wall's maintenance. By disrupting the cell wall, the drug prevents the fungus from maintaining its structure. This mechanism translates into the specific benefit of eliminating the causative fungal agent at the source of the infection.

What side effects are possible with Locasten?

Possible Side Effects and Safety Information

The safety profile for Locasten (Clotrimazole) is primarily characterized by localized adverse reactions, reflecting its topical and intravaginal routes of administration and minimal systemic absorption. The most frequently documented effects involve the application site.


Official Adverse Reactions and Frequency

Adverse reactions are grouped into System-Organ Classes (SOC) in regulatory documents. The most commonly reported effects are categorized under Skin and Subcutaneous Tissue Disorders or Reproductive System Disorders (Genitourinary) [Source 1.7, 2.7].

Classification Symptoms Documented in Regulatory Sources
Common Local reactions like irritated or red skin, pain, and a burning or stinging sensation at the site of application [Source 1.1].
Rare Serious allergic reactions, including Anaphylaxis, which is a rare but officially documented serious adverse event [Source 1.1, 1.4].
Frequency Not Defined Symptoms such as blistering, peeling, edema (swelling), itching, urticaria (hives), and specific vulvar or vaginal discomfort (e.g., cramping, pain) [Source 2.5].

Regulatory Safety Constraints

The official labeling includes specific constraints regarding its use. The product is contraindicated in individuals with a known hypersensitivity to Clotrimazole or any component of its formulation [Source 2.7].

Pregnancy and Latex Integrity: Use during the first trimester of pregnancy should be avoided unless clinically necessary. Additionally, intravaginal preparations may reduce the effectiveness and safety of latex contraceptives (such as condoms and diaphragms), an effect that may last for up to five days after treatment completion [Source 2.4, 2.7].

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory information describes the overdose profile for Locasten (Clotrimazole) based on its low rate of systemic absorption following topical or vaginal application. Due to this minimal absorption, acute overdosage from these routes is classified as unlikely and is not expected to lead to a life-threatening situation.


Documented Overdose Manifestations and Actions

The primary concern addressed in regulatory labeling is accidental oral ingestion. In this specific scenario, clinical symptoms that may become apparent include dizziness, nausea, and vomiting.

Overdose Domain Official Regulatory Statement
Antidote Availability No specific antidote is known for Clotrimazole overdose.
Management Measures Symptomatic and supportive treatment is indicated; gastric lavage may be considered only if clinical symptoms become apparent and the airway can be protected adequately.
Population Note Official documents state there is no data available regarding overdose risk in the paediatric population.

When Urgent Medical Help is Required

Regulatory authorities mandate that if accidental ingestion occurs, individuals must seek professional assistance or contact a Poison Control Center immediately.

Therapeutic Uses of Locasten

Locasten is a widely recognized topical application used to manage a range of skin and mucosal discomforts.

What Locasten Treats: Main Uses and Benefits

Locasten is generally applied in addressing symptoms related to inflammatory or irritative states caused by susceptible conditions. This topical treatment is commonly used to help with conditions presenting with systemic or localized discomfort, such as ringworm, jock itch, and athlete's foot. It is also relevant for easing symptoms related to physical discomfort caused by cutaneous candidiasis (yeast infections of the skin) and other conditions involving episodic or fluctuating manifestations.

Locasten is applied in addressing conditions associated with acute or disruptive episodes, and generally assists with providing supportive relief that helps ease the overall symptom burden. One patient-oriented benefit is captured as: “It supports the patient during difficult episodes by easing distress.” This treatment is useful in scenarios where symptoms escalate temporarily, as it supports general well-being during symptomatic phases. Topical application is considered relevant in conditions characterized by periods of heightened symptoms.


Quick Fact: Relief for Symptoms related to physical discomfort


Regulatory References

  1. NIH MedlinePlus overview of Clotrimazole Topical

Eligibility and Restrictions for Use

Eligibility Scope

Category Official Regulatory Statement
Populations for whom use is allowed (as stated in label) Adults and children over the restricted ages for the specific formulation (topical use established for older children).
Populations for whom use is not recommended (if applicable) Children under 2 years for over-the-counter topical use unless directed by a physician. Use during the first trimester of pregnancy is not recommended unless clearly indicated.
Populations for whom use is contraindicated Individuals with a known hypersensitivity or allergy to clotrimazole or any component of the specific preparation.
Age-related eligibility rules Topical use is restricted for children under 2 years. Some vaginal forms are restricted for use in children under 16 years.
Pregnancy and lactation eligibility status (if explicitly documented) Pregnancy: Conditional use in the first trimester; established use in the second and third trimesters. Lactation: Use with caution; excretion into human milk is unknown.
Eligibility-related restrictions The topical cream is not for ophthalmic use. Vaginal formulations must not be used during menstruation.

Eligibility Classifications (High-Level)

Category Official Regulatory Statement
Eligibility severity classification (as defined in official documents) Contraindicated (Allergy), Restricted/Conditional Use (Pregnancy First Trimester, Children under 2), Established Use (Adults).
Eligibility-context constraints (as defined in official documents) Application Site Restriction (Ophthalmic), Physiological State Restriction (Menstruation), Age Restriction.

Connection to the Overall Eligibility Profile

Official regulatory documents define who can and cannot use the medicine by establishing Absolute Contraindications based on allergy. Eligibility is further defined by Age-Dependent rules that restrict use in infants, and Physiological Status Restrictions that advise caution for nursing mothers and mandate conditional use during the first trimester of pregnancy, all due to the official acknowledgment of limitations in data for systemic exposure.

What should I know about interactions with other medicines?

Interaction Map: Interactions with other medicines and products — official regulatory information for Locasten


Interaction Scope

Detail Description based on Regulatory Documents
Medicinal product categories with documented interactions Oral Anticoagulants; Immunosuppressants; Latex barrier contraceptives; Spermicides.
Specific interacting medicines (if explicitly listed) Tacrolimus, Sirolimus, Warfarin, Dicoumarol, Acenocoumarol.
Mechanistic basis of interactions (only if stated in label) Enzyme Inhibition (CYP3A4) leading to increased plasma concentrations of co-administered systemic drugs; Physical/Chemical Damage to latex devices resulting in efficacy reduction.
Timing-based interaction rules (if applicable) Alternative contraceptive precautions are required for at least five days following the use of the vaginal product.
Population-specific interaction notes (if applicable) Patients with pre-existing hepatic impairment may require monitoring when receiving systemically absorbed forms of the active ingredient.
Interaction-related restrictions Use of tampons, douches, and spermicides must be avoided during treatment with the vaginal product.

Interaction Classifications (High-Level)

Classification Description based on Regulatory Documents
Interaction severity classification (as defined in official documents) Contraindicated Combination for non-drug products (Latex barrier contraceptives/spermicides, due to efficacy failure); Use-with-Caution Combination for certain systemic drugs.
Regulatory basis (EMA / FDA / etc.) EMA Summary of Product Characteristics, FDA Prescribing Information.
Interaction-context constraints (as defined in official documents) Pharmacokinetic interactions are primarily a regulatory caution for the active ingredient due to minimal systemic exposure of topical/vaginal forms.

Resulting Interaction Structure

Official interaction statements:

  • Locasten vaginal product may cause physical damage to latex contraceptives (condoms and diaphragms), which reduces their effectiveness.
  • The product can decrease the effect of spermicides when co-administered.
  • Use of tampons, douches, and spermicides must be avoided during the use of the vaginal product.
  • Co-administration with the immunosuppressants Tacrolimus or Sirolimus may lead to increased plasma concentrations of the immunosuppressant.
  • Interactions with oral anticoagulants (e.g., Warfarin) have been documented to increase the exposure/effect of the anticoagulant with systemically absorbed forms of Clotrimazole.

Connection to the overall interaction profile (2–4 sentences): Regulatory documents define the interaction structure by the documented physical incompatibility with latex contraceptives, necessitating mandatory avoidance and timing separation. The profile also notes the active ingredient's known potential for CYP3A4 inhibition, which may increase the exposure of systemic drugs despite minimal absorption from topical/vaginal use.

Mechanism of Action

How Locasten Works: Mechanism of Action


Disrupting Fungal Cell Membrane Synthesis

Locasten (Clotrimazole) exerts its primary mechanism of action by targeting and inhibiting the fungal enzyme Cytochrome P450 14-alpha-demethylase (CYP51). This interaction blocks the conversion of lanosterol into ergosterol, the primary sterol required for fungal cell membrane structure. The resulting ergosterol deficiency and accumulation of toxic sterol intermediates rapidly compromise the integrity and permeability of the fungal cell wall, leading to the leakage of intracellular contents and ultimately causing fungal cell lysis.


️ Secondary Modulation of Host Ion Channels

In addition to its effect on fungal cells, Locasten is known to inhibit the mammalian Intermediate Conductance Calcium-Activated Potassium Channel (KCa3.1) found in various human cells. This action modulates potassium ion flux, which is related to host cell volume and membrane potential regulation. While separate from the antifungal effect, this constitutes the drug's secondary mechanism of action on host tissue.

Dosage and Administration Information

Locasten is administered through two primary routes, depending on the preparation and the site of infection: topical application onto the skin or intravaginal insertion for mucosal use. The medicine is supplied in specific preparations, such as a 1% cream or solution for dermal application, and 100 mg, 200 mg, or 500 mg tablets or cream for intravaginal use. Dosing follows fixed schedules for both routes of administration.

Application Area Administration Schedule Duration Pattern
Dermal/Topical Apply to the affected area twice daily. Typically ranges from two to four weeks for full treatment.
Intravaginal Inserted once daily, preferably at bedtime. Fixed courses of 1, 3, or 7 consecutive days.

The full prescribed duration of treatment must be completed, even if symptoms appear to improve quickly. For dermal treatment, the affected skin area must be cleaned and thoroughly dried before the product is gently massaged into the site. Intravaginal application is best performed at bedtime, and treatment courses are advised not to be performed during menstruation. Furthermore, administration constraints advise against the concurrent use of products such as tampons, douches, or spermicides during the intravaginal course. Administration is generally approved for children over 3 years of age for dermal infections and for adolescents 12 years of age and older using the intravaginal regimens.

Recent Clinical Evidence

Research Evidence Overview for Locasten (Clotrimazole)

Research Supporting Use for Skin Fungal Infections

Locasten was studied for the specific indications of ringworm, jock itch, and athlete's foot. Research examined Randomized Controlled Trials (RCTs) and comparative clinical trials, where the topical product was often evaluated against a placebo or another active antifungal agent. The studies included adults and adolescents and primarily monitored two key outcomes: the Mycological Status (laboratory confirmation of fungal presence) and tracked the Change in Clinical Signs and patient-reported outcomes describing perceived discomfort like itching.

Research highlights that studies reported measurements related to the rate of mycological status change and patterns of change in clinical signs during the defined observation period. Evidence is limited regarding the use of the topical product for more complex or deep infections, such as those affecting the nails or the scalp. Furthermore, research describing the durability of the response and the long-term outcomes, particularly follow-up durations beyond six weeks, is not fully established.

Studies for Vulvovaginal Yeast Infections

The evidence base for vulvovaginal candidiasis includes a significant number of Randomized Controlled Trials (RCTs), systematic reviews, and meta-analyses. Research explored various Locasten formulations (such as intravaginal tablets or creams) and was evaluated in adult women. The studies monitored two primary types of outcomes: the Microbiological Status (clearance of Candida species) and patient-reported outcomes related to physical discomfort, such as itching and burning.

Studies monitored how symptoms evolved, with findings describing patterns of change in symptom scores and microbiological status over the short term. Data show patterns related to the measured outcomes for Locasten, and research also included comparative trials against other treatments. Data for certain groups remain insufficient, particularly regarding conditions caused by non-albicans Candida species. Research is ongoing to establish the optimal strategy for the long-term prevention of recurrence in women who experience frequent episodes.

Research Gaps and Areas of Uncertainty

This review highlights several areas where more research is needed to provide comprehensive context. A significant limitation is that long-term outcomes are not fully established, as follow-up durations were limited across most studies. Comparative evidence is lacking in some indications, such as Pityriasis Versicolor, where additional head-to-head trials are needed. Findings describe group patterns, not personal outcomes, and evidence highlights what is known—and what is still uncertain—about Locasten.

Key Studies & References

  1. Clotrimazole Pharmacological Class - StatPearls/NCBI Bookshelf
  2. Systematic Review of Clotrimazole for Vulvovaginal Candidosis: Findings on Cure Rates - MDPI
  3. Antifungal (oral and vaginal) therapy for recurrent vulvovaginal candidiasis: a systematic review and meta-analysis - SciELO
  4. Clotrimazole treatment of recurrent and chronic candida vulvovaginitis - PubMed

Frequently Asked Questions (FAQ)

Common questions about Locasten (FAQ)


Q: How quickly does Locasten start working?

Studies and official information indicate that the medicine acts immediately at the application site by targeting the fungal cells. However, due to its minimal systemic absorption, the activity is localized. Clinical trials indicate that visible improvement in symptoms is generally observed over the full prescribed course of treatment.


Q: How long does the effect of Locasten last after taking a dose?

The medicine is designed for localized action at the site of infection. Following intravaginal use, official information suggests fungicidal concentrations can remain in the affected area for up to three days after a single application. For topical use, the action is concentrated at the skin surface due to minimal systemic absorption.


Q: What happens if I miss a dose of Locasten?

Official information suggests applying the missed dose as soon as possible. However, if it is almost time for the next scheduled dose, the missed one should be skipped to return to the regular schedule. It is important not to apply two doses at once.


Q: Is Locasten safe to use long-term?

Official product information defines specific, limited treatment durations, such as 2 to 4 weeks for topical infections. The product is intended for these short-term courses to resolve the infection. It is typically not intended for continuous, prolonged use beyond the maximum duration specified in the label.


Q: Do you need a prescription to get Locasten?

Locasten, when containing Clotrimazole as the single active ingredient in topical or vaginal forms, is often marketed as an Over-the-Counter (OTC) medicine. This classification means the product is widely available for purchase without a prescription in many regulated markets.


Q: Does Locasten affect blood pressure or heart rate?

Due to minimal absorption into the bloodstream from the topical and vaginal products, the official product information primarily lists localized adverse reactions. Systemic effects such as changes in blood pressure or heart rate are not commonly reported side effects.


Q: Can Locasten make you feel drowsy or dizzy?

Central Nervous System (CNS) effects, such as drowsiness or dizziness, are not typically listed in the product’s official safety information. This is because minimal amounts of the medicine are absorbed into the rest of the body when applied topically or vaginally.


Q: Are there any foods or drinks I should avoid while on Locasten?

For the topical and vaginal preparations, regulatory documents do not specify any mandatory food restrictions. Official warnings are instead focused on drug-to-drug interactions with systemic medicines and physical incompatibility with latex-based contraceptives.


Q: Why do some people say Locasten didn't work for them?

Official guidance advises seeking medical evaluation if symptoms do not improve after the advised duration of treatment. This is important to rule out conditions such as an incorrect diagnosis, a more severe underlying issue, or an infection not susceptible to Locasten.


Q: Does taking Locasten require any special monitoring or blood tests?

Due to minimal systemic absorption, no routine monitoring or blood tests are generally required for the topical or vaginal product. However, monitoring may be required for patients with pre-existing hepatic (liver) impairment if using systemically absorbed forms of the active ingredient.


Q: What should I do if I experience a mild side effect from Locasten?

Mild side effects are often localized and temporary. Official labeling advises stopping use and seeking medical attention if symptoms worsen, or if signs of a more serious reaction develop, such as fever, unusual discharge, or rash.


Q: Is it safe to drink alcohol while taking Locasten?

No direct warnings or contraindications regarding the consumption of alcohol are specified for the topical and vaginal preparations in regulatory documents. This is because the medicine is designed for local application with minimal systemic absorption.


Q: Can I crush or split the Locasten tablet?

The intravaginal tablet is designed for whole insertion into the vagina. Official directions for use do not include instructions for crushing or splitting the tablet prior to use. It is intended to be used as supplied.


Q: What's the typical duration of treatment with Locasten?

The typical duration of treatment is defined by the site of infection in regulatory documents. This usually ranges from 2 to 4 weeks for most topical skin infections, and fixed courses of 1, 3, or 7 consecutive days for intravaginal use.


Q: Is there a maximum time someone can stay on Locasten?

Regulatory documents define specific treatment duration limits (e.g., up to 4 weeks for topical use). While a lifetime maximum is not stated, official information advises seeking further medical evaluation if symptoms persist beyond these standard course limits.


Q: Are there any skin-related side effects from Locasten?

Yes, official documents list skin-related side effects, which are mostly localized reactions at the application site. These may include redness (erythema), stinging, burning, blistering, peeling, itching (pruritis), and general irritation.


Q: Does Locasten affect my ability to drive or operate machinery?

According to the official product information, the medicine is not expected to affect the ability to drive or operate machinery. This is attributed to the minimal systemic absorption of the product from the topical and vaginal routes of administration.


Q: Is it common for Locasten to cause stomach upset?

Stomach upset is not a commonly reported side effect for the topical and vaginal forms of Locasten. Regulatory data for the active ingredient show that gastrointestinal side effects primarily occur when the medicine is taken orally, which is not the approved route for this product.


Q: Can Locasten interact with herbal remedies like St. John's Wort?

Regulatory documents flag the active ingredient's known potential to interact with other drugs by inhibiting the CYP3A4 enzyme system. Although no specific herbal remedies are named, caution is generally warranted with any product known to affect this enzyme system.


Q: What are the benefits of using Locasten compared to no treatment?

Clinical trials consistently show that Locasten is significantly more effective than placebo (no treatment) for its approved indications. The documented benefits include achieving both mycological cure (eliminating the fungus) and clinical improvement of infection symptoms.


Q: If I have kidney problems, can I still take Locasten?

Due to minimal systemic absorption of the topical and vaginal products, no specific precautions regarding kidney impairment are commonly listed. Regulatory documents mainly raise a caution for patients with pre-existing hepatic (liver) impairment when using systemically absorbed forms of the active ingredient.


Q: What happens when you stop taking Locasten suddenly?

The official label stresses the importance of completing the full prescribed course of treatment, even if symptoms improve quickly. Incomplete treatment may result in the return of the infection or incomplete eradication of the causative organism.


Q: Is Locasten considered a high-risk medication?

Regulatory information indicates that the safety profile for the topical and vaginal products is characterized primarily by localized reactions. Due to minimal absorption, the product’s use limits the potential for most serious systemic adverse effects.

How should Locasten be stored and disposed of?

Official Storage and Disposal Requirements

Official regulatory documents define specific conditions for storing and disposing of Locasten to maintain its stability and effectiveness.

Storage Requirements

Condition Requirement (Official Statement)
Temperature Store at controlled room temperature, between 20 C and 25 C. Do not store above 30 C and do not freeze.
Protection Keep the medicine protected from light and moisture.
Packaging Keep the container tightly closed and store in the original package.
In-Use Stability If reconstituted, the product is stable for 28 days when stored refrigerated at 2 C to 8 C.
Child Safety Keep Locasten out of the sight and reach of children.

Disposal Requirements

Unused or expired Locasten must not be disposed of in household waste or wastewater (e.g., toilet or sink). Disposal must follow the official Pharmaceutical Waste Protocol, requiring the product to be returned to a pharmacy or designated medication collection site.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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