Usage
Clotrimazole is an antifungal medication primarily used for the treatment of fungal infections of the skin, such as ringworm (tinea), athlete’s foot, jock itch, and yeast infections of the vagina (vaginal candidiasis) and mouth (oral thrush). It is also effective against pityriasis versicolor, erythrasma, and intertrigo. It can also be used for skin conditions with secondary fungal infections. Clotrimazole belongs to the pharmacological class of imidazole antifungals. Its mechanism of action involves inhibiting the synthesis of ergosterol, a crucial component of the fungal cell membrane. This disruption leads to increased permeability of the fungal cell wall, causing leakage of cellular contents and ultimately fungal cell death.
Alternate Names
Clotrimazole is the generic name. Brand names include Canesten, Lotrimin, Mycelex, Gyne-Lotrimin, and Lotrimin AF.
How It Works
Pharmacodynamics: Clotrimazole alters the fungal cell membrane by inhibiting ergosterol synthesis. This inhibition is achieved through interaction with 14-alpha demethylase, a cytochrome P-450 enzyme necessary for converting lanosterol to ergosterol. The resulting increase in cellular permeability leads to the leakage of essential cellular components, ultimately causing fungal cell death. Clotrimazole’s action is specific to fungal cells and doesn’t significantly affect human cholesterol synthesis.
Pharmacokinetics: Absorption of topical clotrimazole is minimal, resulting in low systemic exposure. Following intravaginal administration, about 5-10% of the dose is absorbed. Peak plasma concentrations are reached approximately 3 hours post-application. Absorbed clotrimazole is metabolized in the liver and excreted primarily in the bile. The intravaginal formulation achieves fungicidal concentrations in the vagina for up to 3 days post-application. Oral clotrimazole (troches) is used for local treatment of oropharyngeal candidiasis and isn’t significantly bioavailable systemically. Persistence in saliva is attributed to binding to the oral mucosa.
Dosage
Standard Dosage
Adults:
- Vaginal Candidiasis:
- 100 mg vaginal suppository once daily for 7 days.
- 200 mg vaginal suppository once daily for 3 days.
- 500 mg vaginal suppository as a single dose.
- One applicatorful of 1% vaginal cream once daily for 7 days.
- One applicatorful of 2% vaginal cream once daily for 3 days.
- Skin Infections: Apply a thin layer of cream, lotion, or solution to the affected area twice daily for 2 to 4 weeks.
- Oral Thrush: 10 mg lozenge dissolved slowly in the mouth five times a day for 14 days.
Children:
- Vaginal Candidiasis (12 years and older): The same dosing regimens as adults can be used.
- Skin Infections: Apply a thin layer of cream, lotion, or solution to the affected area twice daily. Duration of treatment varies depending on the infection.
- Oral Thrush (3-17 years): 10 mg lozenge dissolved slowly in the mouth five times a day for 7-14 days.
Special Cases:
- Elderly Patients: No specific dosage adjustments are typically required, but it is advisable to use the minimum effective dose for the shortest duration necessary.
- Patients with Renal Impairment: Dosage adjustment is unlikely to be needed due to low systemic absorption.
- Patients with Hepatic Dysfunction: Dosage adjustment is unlikely to be needed due to low systemic absorption.
- Patients with Comorbid Conditions: Exercise caution in patients with underlying medical conditions.
Clinical Use Cases
Clotrimazole is not typically used in the clinical settings mentioned (intubation, surgical procedures, mechanical ventilation, ICU use, emergency situations).
Dosage Adjustments
Dosage adjustments are generally not required for clotrimazole due to its low systemic absorption. However, individualized dosing considerations may be necessary based on specific patient factors, the severity of the infection, and the site of infection.
Side Effects
Common Side Effects
- Local irritation, burning, stinging, itching, redness, swelling, or peeling at the application site.
- Vaginal irritation, itching, or discharge with intravaginal use.
- Abdominal cramps with intravaginal use.
Rare but Serious Side Effects
- Allergic reactions (rash, hives, itching, swelling, difficulty breathing, dizziness).
Long-Term Effects
No significant long-term adverse effects have been reported with topical or intravaginal use.
Adverse Drug Reactions (ADR)
Severe allergic reactions (anaphylaxis) require immediate medical attention.
Contraindications
- Hypersensitivity to clotrimazole.
Drug Interactions
- May reduce the effectiveness of latex condoms and diaphragms when used intravaginally or on the penis.
- When co-administered with tacrolimus, it may significantly elevate levels and lead to tacrolimus-associated toxicities.
- Vaginally administered progesterone should not be used concurrently due to potential interactions.
Pregnancy and Breastfeeding
- Pregnancy: Clotrimazole is generally considered safe to use during pregnancy, especially topical and vaginal formulations. Avoid using the applicator intravaginally during pregnancy.
- Breastfeeding: Clotrimazole can be used while breastfeeding. Minimal amounts are excreted in breast milk. Take care to prevent infant contact with treated areas.
Drug Profile Summary
- Mechanism of Action: Inhibits ergosterol synthesis, disrupting fungal cell membrane integrity.
- Side Effects: Local irritation, burning, stinging, itching. Rare allergic reactions.
- Contraindications: Hypersensitivity.
- Drug Interactions: May reduce latex contraceptive efficacy. Possible interaction with tacrolimus.
- Pregnancy & Breastfeeding: Generally safe.
- Dosage: Varies based on formulation and infection site.
- Monitoring Parameters: Monitor for treatment response and adverse effects.
Popular Combinations
Clotrimazole is sometimes combined with betamethasone (a corticosteroid) for enhanced anti-inflammatory and antipruritic effects in conditions like tinea infections accompanied by inflammation. Clotrimazole is also combined with hydrocortisone (a corticosteroid) for short-term treatment.
Precautions
- General Precautions: Discontinue if irritation or sensitivity develops.
- Specific Populations: Use with caution in pregnant and breastfeeding women. Avoid using applicators intravaginally during pregnancy. Remove excess cream/ointment from nipples before breastfeeding.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Clotrimazole for vaginal candidiasis?
A: Several dosing options exist: 100 mg vaginal suppository once daily for 7 days, 200 mg vaginal suppository once daily for 3 days, 500 mg vaginal suppository as a single dose, one applicatorful of 1% vaginal cream once daily for 7 days, or one applicatorful of 2% vaginal cream once daily for 3 days.
Q2: How is Clotrimazole used for skin infections?
A: Apply a thin layer of cream, lotion, or solution to the affected area and surrounding skin twice daily for 2 to 4 weeks, or as directed by a physician.
Q3: Can Clotrimazole be used during pregnancy?
A: Yes, clotrimazole is generally considered safe to use during pregnancy, but intravaginal applicators should be avoided. Consult a physician for guidance.
Q4: Is Clotrimazole safe to use while breastfeeding?
A: Yes, clotrimazole can be used while breastfeeding, but precautions should be taken to minimize infant exposure to treated areas.
Q5: What are the common side effects of Clotrimazole?
A: Common side effects include local irritation, burning, stinging, itching, redness, and swelling at the application site.
Q6: What should be done if a patient experiences an allergic reaction to Clotrimazole?
A: Discontinue use immediately and seek medical attention.
Q7: How does Clotrimazole work against fungal infections?
A: Clotrimazole inhibits ergosterol synthesis, a critical component of the fungal cell membrane. This disrupts the membrane’s integrity leading to fungal cell death.
Q8: Are there any drug interactions with Clotrimazole?
A: Clotrimazole can reduce the effectiveness of latex condoms and diaphragms. Concurrent use with Tacrolimus can increase Tacrolimus blood levels significantly. It is important to inform your physician about all other medications you are taking.
Q9: What is the dosage for Clotrimazole troches for oral thrush?
A: The typical dosage is one 10 mg lozenge dissolved slowly in the mouth five times a day for 14 days.
Q10: Can children use Clotrimazole?
A: Yes, but the dosage and formulation may vary depending on the child’s age and the specific infection. Always consult a healthcare professional before administering clotrimazole to children.
