Onychomycosis Lecture Flashcards
Onychomycosis
Most common nail disorder
Toenails»_space;> fingernails
Dermatophytes
Trichophyton rubrum
Trichophyton mentagrophytes
Yeast
Candida albicans
Candida parapsilosis
Nondermatophytes
Aspergillus
Scopulariopsis
Why treat?
Quality of life Physiological stress Pain Inflammation Peripheral circulation Foot ware Infection potential
Types of onychomycosis
DISTAL SUBUNGUAL ONYCHOMYCOSIS
White superficial onychomycosis
Proximal subungual onychomycosis
Candida Onychomycosis
Distal Subungual Onychomycosis
Most common
Infection begins in the distal area of the nail bed (tip of the toe)
THICK toenail
White superficial
Toe nail infection only
Involves the surface of the nail –> not a thicker nail
Nail is soft, dry, and easily scraped off
Proximal Subungual Onychomycosis
Infection that beings at the nail bed and moves out
Leads to separation from nail bed
Dystrophic
Nail deformities
- Increased risk of infection in immunocompromised and diabetic patients
Candida Onychomycosis
Immunocompromised Seen in dishwashers Nails appear opaque and does not crumple Yellow-brown in collor FINGER NAILS
Differential diagnosis
Psoriasis Pseudomonal infections Medications Exzema Dermatitis Trauma Ischemic conditions (poor blood flow)
People at risk
Diabetes
Immunosuppressant and systemic antibiotics
HIV/AIDS: younger age –> proximal subungual onychomycosis
Geriatrics >60
Institutional living
Athletes
Health clubs
Clinical presentation/symptoms
Hyperkeratosis (thickening of the nail)
Discoloration of the nail (white or brown)
Brittleness
Onycholysis (separation of the nail from the bed
Paronychial inflammation
Recurrent tinea pedis
Pain
Diagnosis
History/clinical symptoms KOH prep of nail clippings Fungal culture Nail biopsies - Need test as well as physical observations
Ideal agents
Good concentration in the nail bed High clinical/mycologic cure rate Low rate of relapse Short term therapy Few ADR's and interactions Cost effective
Treatment options
Nail removal Topiocal therapy (ineffective) Griseofulvin Ketaconazole (DO NOT USE) Itraconazole Fluconazole Terbinafine
Topical Nail Therapy
Nail lacquers (ciclopirox- PenLac)
Antifungal agents: solutions or creams (clotrimazole, tolnaftate, terbinafine) or powders (tolnaftate
– Low cure rate and high relapse rate
History of high transaminase levels or have liver disease and want something for fungal infections?
PenLac bc others raise transaminase levels
Cons of Topical Nail therapy
Cannot penetrate harden nail mass
Requires multiple daily applications and long duration of therapy
- Can be used with other oral treatments
Griseofulvin
First oral agent; Fungistatic
Microsize: need to take with a fatty meal to increase adsorption
Ultramicrosize: Increased absorption
- Monitor Baseline AST, ALT, and CBC and repeat AST and ALT if treatment last >6 wks
Dosage of Griseofulvin
500 mg QD-BID
Griseofulvin Disadvantages
High rate of resistance, high rate of relapse, low cure rate, long duration, intolerable adverse drug reactions
ADR’s: skin rashes, urticaria, GI, photosensitivity, toxic epidermal necrolysis (sore throat, fever, rash)
- Potential cross reactive with penicillin
Griseofulvin Drug Interactions
Anticoagulants, oral contraceptives, cyclosporine and salicylates
Phenobarbital decrease serum concentrations
Fluconazole (Diflucan)
Fungistatic –> inhibits the synthesis of ergosterol
Toe nails
Fluconazole (Diflucan) Advantages
Good nail bed and matrix penetration
Detect in toenails 6 months after
Good absorption not influence by gastric acid, food, antacids or H2 blockers
Fluconazole (Diflucan) Disadvantages
Lacks indication
Not extensively studied
Fluconazole (Diflucan) Dosage
150, 300, or 450 mg week for 3 months
3-12 months of treatment
80% excreted unchanged via urine
Fluconazole (Diflucan) Monitor & Interaction
Baseline AST, ALT, CBC; remonitor >6 wk therapy
Increases the effects of warfarin, cyclosporine, theophyline, phenytoin, sulfonylureas
QT prolongation and decreases oral contraceptives
Fluconazole (Diflucan)ADR’s
GI- nausea, diarrhea and ab pain, elevated liver enzymes
Pulse dosing decrease incidence
Intraconzaole (Sporanox)
Fungistatic- inhibits the synthesis of ergosterol
For onychomycosis; good concentration in nail matrix and bed
Detectable for 6 months after
Intraconzaole (Sporanox) Dosage
Toenails: 200 mg daily for 12 weeks
Fingernails: 200 mg BID for 3 days per month for 2 months (separated by 3 weeks)
Intraconzaole (Sporanox) Monitor
Baseline AST, ALT, CBC; recheck monthly
Intraconzaole (Sporanox) Drug Interactions
Warfarin, H2 blockers, PPI, DDI, Ritonavir, Indiavir, Benzodiazepines, Lovastatin, Simvastatin, Cyclosporine, Tacrolimus, Phenytoin, Phenobarbital, carbamazepine, rifamycins
Intraconzaole (Sporanox) ADR’s
GI- nausea, vomiting, diarrhea, ab pain Headache Dizziness Rash ELEVATED LIVER ENZYMES
Intraconzaole (Sporanox) FDA Warnings
Hepatoxicity
CHF, cardiac dysfunction or a history of CHF
- Discontinue if signs or symptoms of CHF
Intraconzaole (Sporanox) Disadvantages
Drug interactions
Expensive
Must be taken with full meal
Acidic environment for absorption - no antacids, H2 blockers, PPIs; need achlorhydria - soda increases adsorption
Terbinafine (Lamisil)
First line therapy
FDA indicaiton
More effective than itraconzaole
Fungicidals
Terbinafine (Lamisil) Dosage
Fingernail: 250 mg QD for 6 weeks
Toenails: 250 mg QD for 12 weeks
Terbinafine (Lamisil) FDA warnings
Hepatotocicity (rare)
- Liver failure and death
- Not indicated for chronic or active hepatic disease
- NO LIVER DISEASE PATIENTS*
Terbinafine (Lamisil) Monitor and interactions
Baseline AST, ALT, CBC; recheck after >6 wk of treatment
Tricyclic antidepressants, SSRI’s (fluoxetine, paroxetine)
Venlafaxine and cyclosporine
Terbinafine (Lamisil) ADRs
GI- diarrhea, ab pain, nausea, and flaulence
Rash
TASTE DISTRUBANCES
ELEVATED LIVER ENZYMES
Terbinafine (Lamisil) Advantages
Fewer drug interactions, fewer ADR’s, fungicidal activity, pregnancy category B
Therapeutic considerations
Concomitant disease states (don't treat liver disease patients) Drug interactions (azoles) ADR's (terbinafine and fluconazole = better tolerated) How much they cost
