General

Pronunciation:
gri-see-oh-ful-vin

Trade Name(s)

• Grifulvin-V
• Gris-PEG

Ther. Class.

antifungals

(systemic)

Indications

• Treatment of various tinea infections.
• Should not be used for superficial infections that may respond to topical antifungals.

Action

Inhibits mitosis of fungal cells. Deposits in precursor cells of hair, skin, and nails, making them resistant to fungal invasion.

Therapeutic Effect(s):

Growth of new cells that are resistant to invasion by fungi.

Pharmacokinetics

Absorption: Microsize preparations are variably (25–70%) absorbed after oral administration. Ultramicrosize products are almost completely absorbed.

Distribution: Mostly deposited in keratin layer of skin; also found in liver, fat, and skeletal muscle.

Metabolism and Excretion: Metabolized by the liver, some excreted in feces and perspiration.

Half-life: 9–24 hr.

TIME/ACTION PROFILE (antifungal activity)

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity
• Severe liver disease or porphyria.

Use Cautiously in:

• OB:  Lactation: Safety not established
• Possible cross-sensitivity with penicillin.

Adverse Reactions/Side Effects

Derm: ERYTHEMA MULTIFORME, photosensitivity, rashes, STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS

EENT: hearing loss

GI: flatulence, diarrhea, epigastric distress, extreme thirst, HEPATOTOXICITY, nausea, vomiting

Hemat: leukopenia

Neuro: headache, dizziness

Misc: hypersensitivity reactions including SERUM SICKNESS, lupus-like syndrome

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

• Tachycardia, flushing, and ↑ CNS depression may result if taken concurrently with  alcohol.
•  Phenobarbital  ↓ blood levels and may ↓ effectiveness.
• May ↓ the effectiveness of  warfarin  or  hormonal contraceptive agents.

Drug-Food:

Absorption is ↑ by fatty foods.

Route/Dosage

Microsize

PO (Adults): Tinea pedis, onychomycosis: 500 mg every 12 hr.  Tinea capitis, corporis, or cruris: 250 mg every 12 hr  or  500 mg once daily.

PO (Children  >23 kg): 125–250 mg every 12 hr  or  250–500 mg once daily.

PO (Children 14–23 kg): 62.5–125 mg every 12 hr or  125–250 mg once daily.

Ultramicrosize

PO (Adults):   Tinea pedis, onychomycosis: 375 mg every 12 hr.  Tinea capitis, corporis, or cruris: 187.5 mg every 12 hr or 375 mg once daily.

PO (Children  >27 kg): 187.5–375 mg once daily.

PO (Children  16–27 kg): 125–187.5 mg once daily.

Availability (generic available)

Microsize tablets: 500 mg

Oral suspension (microsize): 125 mg/5 mL

Ultramicrosize tablets: 125 mg, 250 mg

Assessment

• Assess skin at site of fungal infection routinely during therapy.
• Assess patient for allergy to penicillin; potential cross-sensitivity exists.
• Assess for rash periodically during therapy. May cause Stevens-Johnson syndrome or toxic epidermal necrolysis. Discontinue therapy if severe or if accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis and/or eosinophilia.

Lab Test Considerations:

Monitor CBC, serum creatinine, and hepatic functions periodically during treatment.

• Monitor urinalysis periodically during therapy. May rarely cause proteinuria.

Implementation

• Concurrent use of a topical agent is usually required.

  • Ultramicrosize griseofulvin 250 mg provides serum concentrations equal to that of microsize griseofulvin 500 mg.
• PO Administer with or after meals, preferably meals with high fat content, to minimize GI irritation and increase absorption.

Patient/Family Teaching

• Instruct patient to complete full course of therapy; several wk of therapy may be necessary. If a dose is missed, take as soon as remembered, but do not take if almost time for next dose.
• Instruct patient on hygiene to control sources of infection or reinfection.
• May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
• Advise patient to wear sunscreen and protective clothing to prevent photosensitivity reaction.
• Caution patient not to drink alcohol while taking this medication.
• Advise patient to notify health care professional if rash, sore throat, fever, diarrhea, or soreness of mouth or tongue occurs.
• Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
• Advise female patients taking oral contraceptives to use an additional nonhormonal form of contraception during therapy and until next menstrual period and to notify health care professional if pregnancy is planned or suspected.
• Emphasize importance of follow-up examinations to monitor progress of therapy.

Evaluation/Desired Outcomes

Resolution of signs and symptoms of fungal infection. To prevent relapse, treatment may take wk to mo and should continue until organism is completely eradicated as determined by clinical or laboratory testing. Tinea capitis usually requires treatment for 8–10 wk; tinea corporis, 2–4 wk; tinea pedis, 4–8 wk; onychomycosis, at least 4 mo for fingernails and at least 6 mo for toenails (recurrence rates for toenails are very high).