Griseofulvin

Griseofulvin is an antifungal (anti-fungal) drug used to treat fungal infections of the skin, hair, and nails. It is effective against various types of dermatophytes, such as Trichophyton (the cause of athlete's foot, ringworm), Microsporum, and Epidermophyton.

Griseofulvin works by disrupting the structure and function of the microtubules in the fungal cell skeleton, which prevents the fungal cells from dividing. This stops the spread of infection by making the fungal cells more vulnerable to the host's immune system.

Indications Griseofulvin

1. Dermatophytosis (trichophytosis, microsporia, epidermophytosis) are fungal infections of the skin caused by dermatophytes that affect the skin, hair and nails.
2. Onychomycosis (fungal nail infections) is a disease in which fungi affect the nail plate, causing its deformation, discoloration and peeling.
3. Ringworm (Tinea) is a fungal infection of the scalp that can lead to baldness and skin inflammation.

Release form

Griseofulvin usually comes as tablets or capsules for oral use.

Pharmacodynamics

Griseofulvin works by inserting itself into the structure of keratin (the protein that makes up the bulk of skin, hair and nails), making it less accessible to fungi and preventing their growth and reproduction. This is especially important for treating dermatophyte infections such as trichophytosis (ringworm), microsporia and athlete's foot, which affect the skin, hair and nails.

Pharmacokinetics

• Absorption: Griseofulvin is absorbed from the gastrointestinal tract, primarily from the duodenum. Food intake may increase its absorption.
• Metabolism: The drug undergoes extensive metabolism in the liver, including hydroxylation and demethylation.
• Excretion: Metabolites are excreted mainly via bile and feces. A small amount is excreted via the kidneys.
• Half-life: The half-life of griseofulvin can be quite long, requiring long-term treatment.
• Time to reach maximum blood concentration (Tmax): Typically Tmax is 4 to 5 hours after taking the drug.
• Protein binding: Griseofulvin is highly bound to plasma proteins, primarily albumin.
• Time of action: The long-lasting action of griseofulvin is due to its accumulation in keratinized tissues such as skin, hair and nails.

Dosing and administration

Method of administration and dosage

The dosage and route of administration of griseofulvin may vary depending on the form of the drug (tablets, suspension), the type of infection, the patient's age and weight. It is important to follow the doctor's instructions and the directions on the drug package. Below are general recommendations:

1. For adults and children over 12 years old:
   • The usual dose is 500 mg to 1000 mg per day, depending on the type and severity of the infection.
   • The dosage can be divided into several doses throughout the day.
2. For children weighing less than 50 kg:
   • The usual dose is 10 mg to 20 mg per kilogram of body weight per day.
   • The dose is also divided into several doses.

Method of administration

• Griseofulvin should be taken with fatty foods to improve its absorption.
• It is recommended to drink plenty of fluids throughout the day to help eliminate the drug from the body.
• The duration of treatment depends on the location and severity of the infection, but the course usually lasts several weeks to several months, as fungal infections respond slowly to treatment.

Note

• Do not stop treatment or change the dosage without consulting your doctor, even if your symptoms improve.
• Completing the full course of treatment helps prevent recurrence of the infection.

Use Griseofulvin during pregnancy

Griseofulvin is not recommended for use during pregnancy due to potential risks to the developing fetus. Here are some key points to consider:

Risks to the fetus:

Griseofulvin has been shown to be teratogenic in animal studies, meaning it may cause birth defects in the fetus. Although direct evidence in humans is limited, due to these animal studies and the potential risks, griseofulvin is considered unsafe for use during pregnancy.

Recommendations for pregnant women:

• Avoid Use: Pregnant women should avoid using griseofulvin. If a woman plans to become pregnant or discovers that she is pregnant while taking this drug, she should consult her doctor immediately.
• Talk to your doctor: Your doctor may suggest alternative treatments for yeast infections that are safer to use during pregnancy.

Other precautions:

• Contraception: Women of childbearing potential receiving griseofulvin are advised to use effective contraception during treatment and for a period after its completion to avoid pregnancy.
• Monitoring: If pregnancy occurs during treatment with griseofulvin, it is important to carefully monitor the health of both the mother and the fetus.

Contraindications

1. Known individual intolerance: People with known individual intolerance to griseofulvin or other antifungal agents of this class should avoid its use.
2. Hepatic impairment: Since griseofulvin is metabolized in the liver, its use may be contraindicated in patients with hepatic impairment or other liver disease.
3. Porphyria: Griseofulvin may worsen symptoms of porphyria and should be used with caution in patients with this condition.
4. Pregnancy and breastfeeding: The use of griseofulvin during pregnancy and breastfeeding may be contraindicated or require special attention. The physician should decide whether the use of the drug is necessary in these cases.
5. Paediatric population: The use of griseofulvin in children may be limited and it should be used with caution in children, especially infants and young children.
6. Alcohol: It is recommended to avoid drinking alcohol during treatment with griseofulvin, as it may increase the negative side effects of the drug on the liver.

Side effects Griseofulvin

1. Allergic reactions: In rare cases, griseofulvin can cause serious allergic reactions, including hives, itching, swelling of the face or lips, and difficulty breathing.
2. Gastrointestinal disorders: The most common side effects include nausea, vomiting, diarrhea, and abdominal pain.
3. Headaches and dizziness: Some patients report headaches and dizziness while taking the drug.
4. Fatigue: Griseofulvin may cause you to feel tired or weak.
5. Photosensitivity: One known side effect of griseofulvin is increased sensitivity to sunlight, which may result in sunburn or reddening of the skin when exposed to ultraviolet light.
6. Menstrual disturbances: In women, griseofulvin may cause some changes in the menstrual cycle.
7. Effects on the liver: Since griseofulvin is metabolized in the liver, it may affect liver function, which is manifested by changes in liver enzyme levels.
8. Mental Changes: In very rare cases, griseofulvin may cause mental changes, including confusion, anxiety, or depression.

Overdose

1. Gastrointestinal symptoms: Nausea, vomiting, diarrhea and abdominal pain are often the first signs of overdose.
2. Neurological symptoms: Dizziness, headache, fatigue, and even confusion may occur at high doses of the drug.
3. Skin reactions: Griseofulvin may cause photosensitivity, which is aggravated by overdose, resulting in severe skin burns when exposed to sunlight.
4. Allergic reactions: In rare cases, serious allergic reactions may occur, including hives, swelling, and difficulty breathing.

Interactions with other drugs

1. Antifungal drugs: Combination of griseofulvin with other antifungal drugs may cause an increase or decrease in the effect of other drugs.
2. Anticonvulsants: Griseofulvin may decrease the effectiveness of anticonvulsants such as carbamazepine and phenytoin.
3. Antineoplastic drugs: Interaction with antineoplastic drugs such as cyclophosphamide may increase their toxicity.
4. Antibiotics: Combination with antibiotics such as tetracyclines and ampicillin may reduce their effectiveness.
5. Contraceptives: Griseofulvin may reduce the effectiveness of oral contraceptives, so it is recommended to use alternative methods of contraception.
6. Drugs metabolized in the liver: Griseofulvin may affect the metabolism of other drugs metabolized in the liver, which may lead to changes in their blood concentrations.