Griseofulvin

About Griseofulvin

Griseofulvin is taken up into new skin, hair and nail and stops dermatophyte fungi dividing, so the infection clears as infected tissue grows out. The label covers tinea of the scalp, body, feet, groin, beard and nails, and nothing else: it does not treat yeast or bacterial infections. Treatment depends on growth: the label gives four to six weeks for scalp ringworm, two to four for the body, four to eight for the feet, at least four months for fingernails and at least six for toenails.

The two tablet types are different products. Ultramicrosize griseofulvin is absorbed more efficiently, so the label doses it at roughly two-thirds the microsize amount: a usual adult dose is 500 mg a day of microsize but 375 mg of ultramicrosize, and children over two are dosed by weight on the same principle. A prescription names one, and the pharmacist does not swap it without the prescriber. The microsize label says absorption improves with a high-fat meal, and with milk in children.

Rash and hives are the most common side effects, with nausea, headache and sun sensitivity. Liver injury and severe skin reactions are the serious warnings, so liver tests and blood counts are checked on longer courses. It must not be taken in pregnancy or with porphyria or liver failure, and because it is made from a Penicillium mold, cross-sensitivity with penicillin is possible. The label tells men to wait at least six months after finishing before fathering a child, and warns women that it can make birth control pills fail.

Taking Griseofulvin

How to take it

Once a day or in divided doses, as prescribed, for the full course even when the skin looks clear. The microsize label says a high-fat meal improves absorption, and milk does in children. Shake the suspension before measuring each dose; ultramicrosize tablets can be crushed onto applesauce.

If you miss a dose

Take it as soon as you remember unless it is almost time for the next dose; then skip it. Do not take a double dose.

Storage

Tablets at room temperature in a tight, light-resistant container; keep the suspension closed, away from light, and do not freeze it. Keep out of reach of children.

Interactions to know about

It weakens warfarin and lowers cyclosporine levels, and barbiturates lower its own levels. It can make estrogen birth control pills fail, and the label warns it can intensify alcohol. Avoid strong sun and sun lamps, and tell the prescriber about lupus, liver disease or porphyria. Stop and seek care for a spreading rash, yellowing skin or dark urine.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Griseofulvin differs from pharmacy to pharmacy

Griseofulvin is an old generic but an uncommon prescription, so few pharmacies keep every form in stock and the quote depends on what is on the shelf; one that must order it may price it as a slow-moving item. The suspension is priced by the bottle, and a child’s course can need several.

Courses run for weeks to months, so a prescription for the whole course carries one dispensing fee while monthly fills carry one each; nail infections mean the longest courses.

Ways to pay less for Griseofulvin without insurance

• If the course length is known, ask for it all on one prescription, so you pay one dispensing fee.
• For a child, ask the prescriber whether crushed ultramicrosize tablets on applesauce, which the label allows, would do instead of the suspension.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Griseofulvin

1. 1.Is this the microsize or ultramicrosize form, and is the dose written for it?
2. 2.Should I take it with a fatty meal or milk?
3. 3.How long is the course, and when are my liver tests due?
4. 4.Does it affect my birth control pill, blood thinner or penicillin allergy?

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