Griseofulvin: What Is It and What Is It Used For?

Griseofulvin is an antifungal drug used in the treatment of scalp, nail and skin infections. How to use it safely?

Reviewed and approved by the doctor Diego Pereira.

Written by Carmen Martín

Last update: 26 May, 2023

Griseofulvin is a drug that was developed in 1939 in Oxford. It’s used to treat fungal infections, especially in the hair and nails; it’s therefore considered an antifungal. Although it’s available in several forms of administration, the oral route is the most common.

This has an advantage in effectiveness over other antifungal drugs, however, it also carries certain risks. For this reason, it should be used with caution, especially if you are taking other medications or supplements. We tell you everything you need to know about it. Read on!

What is griseofulvin used for?

Griseofulvin is an antifungal drug. This means that it’s intended to treat infections caused by fungi. For example, ringworm, which can be caused by different species (fungi of the genera Microsporum, Epidermophyton, and Trichophyton).

It’s marketed in different ways from country to country. Both generic and brand-name drugs are available (the most typical is Fulcin®). In this case, the objective is to treat infections affecting the hair, nails, or skin.

How does it work?

Griseofulvin stops infections caused by certain fungi. Its mechanism of action is to prevent the fungus from multiplying and spreading to new cells.

It does so by destroying certain structures of the fungus that are involved in cell division. Specifically, it inhibits the mitosis of the fungus by destroying cell microtubules.

The drug is deposited in the cells of the body that are responsible for synthesizing keratin. These are present in the skin, nails, and hair. These are the places where it exerts its antifungal action.

Its effects are usually felt between the second and fourth day of treatment. However, a total cure of the infection may take weeks or months. This varies depending on the location and extent of the fungus.

It’s administered orally because it’s absorbed through the intestinal mucosa. The drug has a half-life in blood of about 24 hours. Afterwards, it’s metabolized in the liver and eliminated through urine and feces.

Precautions before using griseofulvin

As with any other medication, there are certain aspects to keep in mind before taking griseofulvin. First of all, some people are allergic to this substance. Therefore, it’s possible that a severe allergic reaction may occur.

If this is the case, symptoms include swelling of the throat, difficulty breathing, as well as hives and other manifestations. Airway obstruction can be life-threatening. It’s essential to go to the emergency room if this occurs.

On the other hand, the drug may interact with a number of substances. One of them is alcohol. It can make the person more sensitive to the effects of alcohol, leading to a higher risk of intoxication.

Precautions if you have certain diseases

Griseofulvin can aggravate or complicate some pathologies. As it’s metabolized in the liver, it shouldn’t be administered to people with liver failure or cirrhosis.

The same applies to people suffering from systemic lupus erythematosus, or porphyria. The latter is a genetic disease that affects the blood. In both conditions, administration of this drug may cause a worsening of symptoms.

Other warnings about griseofulvin

It isn’t recommended for pregnant women, women who have just given birth, or women who are breastfeeding. During pregnancy, the drug may cross the placenta and harm the fetus.

In the case of breastfeeding, it seems to pass into the breast milk. Therefore, it’s advisable to contact a physician before starting this treatment. It shouldn’t be used in children under two years of age, as there’s no evidence of its safety, dosage, and efficacy.

Possible side effects of griseofulvin

Griseofulvin, like any other drug, isn’t free of side effects. They don’t always appear, but they should be taken into account. Moreover, there are some that are more frequent than others. We explain these in the following sections.

Common side effects

Common side effects include skin rashes, stomach pain, and diarrhea. Nausea, vomiting, and dizziness may also occur.

Some people experience numbness or tingling in the extremities. Fungal infections in the mouth may even occur. Finally, it has been found to cause headaches, confusion, and insomnia.

Side effects of concern

Although less common, some people experience side effects of greater concern. One of these we have noted before – severe allergic reactions. These are also called anaphylaxis. This should be treated urgently.

In excess amounts, or in sensitive patients, liver damage is possible. When this occurs, tiredness and weakness may appear. Jaundice, loss of appetite, and stomach pain are also common. Similarly, bruising is likely to occur more easily (due to impaired clotting).

Interaction with other medications

Another important thing to be aware of is that it can interact with other medications. According to a publication by Mayo Clinic, it may also interact with vitamin or herbal supplements. It may result in toxic effects or prevent the drugs from being effective.

Drug interactions

When it interacts with other drugs, this drug often decreases the effectiveness of those drugs. This is because it causes the liver to metabolize them faster. As a result, the presence of these drugs in the body decreases and they fail to work properly.

First of all, it can affect birth control pills. When a woman is treated with griseofulvin, it’s recommended that she use other contraceptive methods. For example, barrier methods. If not, she could become pregnant. Other drugs with which interactions occur are the following:

• Warfarin. It’s an anticoagulant used to prevent cardiovascular events, such as thromboembolism or heart attacks.
• Salicylates, such as aspirin (acetylsalicylic acid).
• Cyclosporine.
• Certain barbiturates, such as phenobarbital.

Recommendations for the use of griseofulvin

In order to use this drug correctly, it’s important to know how to administer it and the recommended dosage. According to a publication of the Clínica Universidad de Navarra, this can vary depending on the patient.

It should be the physician who chooses the most appropriate dose according to age, infection, and other influential factors. The oral dose usually used in adults varies from 250 to 500 milligrams every 12 hours. Also, 125 milligrams every 6 hours can be administered.

Treatment should be maintained until the infection is completely eradicated. This may take weeks or months.

If it’s a tinea capitis (scalp infection), higher doses may be recommended. Also, if the infection is on the skin, less treatment time is usually required. On the other hand, if it’s io the nails, it’s usually extended for up to six months.

Children should take 10 milligrams per kilogram per day. In these cases, the gram of griseofulvin per day shouldn’t be exceeded. As in adults, it can be taken once every 12 hours or once a day.

It’s recommended to take the drug after eating foods rich in fats. For example, after eating whole milk or cheese. The reason is that fats improve its intestinal absorption.

What to remember

Griseofulvin is an antifungal drug. Like any other medication, it should be taken with caution, as it isn’t without side effects. In addition, it can interact with other substances and medications.

Therefore, it should always be prescribed by a physician. Likewise, it’s essential that the physician knows about any medication the patient is taking, as well as their medical history. This is the only way to prevent complications.