Griseofulvin microsize (brand Grifulvin V no longer available) and griseofulvin ultramicrosize (brand Gris-PEG) are antifungal medications used to treat certain fungal infections of the skin, hair, and nails. Some examples of such infections include different types of ringworms, even tinea capitis (an infection on the scalp). Griseofulvin is taken by mouth, typically 1 to 3 times daily. Typically, your provider only prescribes griseofulvin if other topical antifungal medications haven't worked for you. Possible side effects include skin rash, nausea, diarrhea, and oral thrush (yeast infection in the mouth).
Certain fungal infections, including:
Griseofulvin is an antifungal. It stops the fungi causing your infection from growing and multiplying (fungistatic).
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Blistering, peeling, or loosening of the skin
chills
joint or muscle pain
red, irritated eyes
sores, ulcers, or white spots in the mouth or on the lips
unusual tiredness or weakness
Less common
Confusion
increased sensitivity of the skin to sunlight
soreness or irritation of the mouth or tongue
Rare
Black, tarry stools
cloudy urine
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
numbness, tingling, pain, or weakness in the hands or feet
painful or difficult urination
shortness of breath
swollen glands
unusual bleeding or bruising
yellow eyes or skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Trouble with sleeping
Incidence not known
pain or discomfort in the chest, upper stomach, or throat
unable to sleep
white patches in the mouth or throat or on the tongue
white patches with diaper rash
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Microsize version is available in a liquid for people who have trouble swallowing pills
Good option when other topical medications fail
Can be used in both children and adults
Available as a lower-cost generic
Ultramicrosize tablets can be crushed and sprinkled onto applesauce
Not safe during pregnancy
Might make birth control less effective
Can cause allergic reaction if you're allergic to penicillin
Can intensify the effects of alcohol
Takes several weeks or months to work
Your provider might recommend for you to take griseofulvin with a fatty meal or milk. This can help your body absorb the medication better.
Avoid alcohol when taking griseofulvin. Drinking alcohol while you're on griseofulvin can cause nausea, vomiting, flushing, and fast heartbeat.
If whole tablets are hard to swallow, griseofulvin ultramicrosize tablets can be crushed and sprinkled onto 1 tablespoonful of apple sauce. The mixture should then be swallowed right away without chewing. Alternatively, you can ask your provider about the liquid version.
If you're using the liquid form of griseofulvin, shake the bottle well before measuring each dose. Be sure to use a medication dose cup, spoon, or syringe to measure out your dose. Using household spoons might cause you to take the wrong amount of griseofulvin.
Griseofulvin might cause certain types of hormonal birth control to not work as well. This can lead to unplanned pregnancies, irregular menstrual cycles, and breakthrough bleeding. You should use a back-up method of protection such as condoms and diaphragms to prevent pregnancy while on griseofulvin.
Let your provider know if you're allergic to penicillin. Griseofulvin is made from certain species of penicillin and might trigger an allergic reaction. Keep in mind that people with penicillin allergies have taken griseofulvin without any problems. But your provider might want to consider other antifungals for you depending on how severe your allergy is.
Griseofulvin has lowered sperm production in animal studies. Although the effects on sperm are unclear in humans, it's recommended that males wait at least 6 months after finishing griseofulvin before trying to conceive a child.
Griseofulvin can make your skin more sensitive to the sun, which means you might sunburn more easily. This can happen even during the winter and on overcast days. Make sure to avoid sun exposure and wear protective clothing when outside while you're taking griseofulvin.
Griseofulvin can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Very rarely, people have developed severe, potentially life-threatening skin reactions (e.g., Stevens-Johnson syndrome (SJS)) after starting griseofulvin. Seek medical attention right away if you notice a new or severe rash, a rash accompanied by a fever, unexplained blisters, or new sores inside your mouth.
Risk factors: History of liver problems | Current liver problems
Very rarely, griseofulvin causes life-threatening liver damage or liver failure. Your risk of this is higher if you have or have had liver problems. Your provider will likely order blood tests for you regularly to check your liver health. If you experience unexplained stomach pain, nausea or vomiting, dark urine, pale stools, yellowing of your skin or white part of your eyes, contact your healthcare provider right away.
Don't take griseofulvin during pregnancy. There have been cases of birth defects in babies born to mothers who took griseofulvin, and it has been shown to cause harm when taken during pregnancy in animal studies. You might be asked to take a pregnancy test before starting griseofulvin. Since griseofulvin might make hormonal birth control less effective, you should use a method of birth control that uses no hormones (condoms, diaphragms, copper IUD) while taking griseofulvin. If you become pregnant, stop taking griseofulvin right away and talk to your healthcare provider.
The length of treatment with griseofulvin ranges from 2 weeks to 6 months, depending on the type of infection you have.
Microsize tablets and oral suspension:
Adults: The typical dose is 500 mg by mouth per day. It can be taken all at once or split in to 2-3 smaller doses and taken throughout the day.
Children ages 2 years and older: Your child's provider will determine their dose will depend on your child's body weight. The typical dose is 10 mg/kg per day, up to 500 mg per day. The total daily dose is typically split into smaller doses and taken throughout the day.
Ultramicrosize tablets:
Adults: The typical dose is 375 mg by mouth per day. It can be taken all at once or split up throughout the day. For more stubborn fungal infections, a dose of 750 mg per day (split up into doses throughout the day) might be required.
Children over 2 years old: Your child's provider will determine their dose will depend on your child's body weight. The typical dose is 7.3 mg/kg per day, up to 375 mg per day.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Have been diagnosed with porphyria
Liver failure
Pregnancy
Certain fungal infections, including:
Ringworm
Jock itch
Athlete's foot
Tinea versicolor (a fungal infection that causes discolored patches on the skin)
Skin yeast infection caused by Candida
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Olson, J. M., et al. (2023). Griseofulvin. StatPearls.
Chartwell RX, LLC. (2022). GRISEOFULVIN MICROSIZE- griseofulvin tablet [package insert]. DailyMed.
Sandoz Inc. (2018). ULTRAMICROSIZE GRISEOFULVIN- ultramicrosize griseofulvin tablet, coated [package insert].
Centers for Disease Control and Prevention. (2021). Candida infections of the mouth, throat, and esophagus.
ScienceDirect. (n.d.). Griseofulvin.
National Organization for Rare Diseases. (2022). Porphyrias.
Tucker, D., et al. (2023). Seborrheic dermatitis. StatPearls.
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