Common drugs Used In Dermatology Flashcards
What are the oral antifungals?
3
- Griseofulvin
- Terbinafine (Lamisil)
- Itraconazole (Sporonox)
Oral antifungals
- Used for what?
- Scalp fungal infection Rx (first and second line?)
- Nail fungal infection Rx (first and second line?)
- Used for treatment of scalp and nail fungal disorders
- Scalp
- First line griseofulvin
- Second line terbinafine (Lamisil) - Nails
- First line terbinafine (Lamisil)
- Second line itraconazole (Sporanox)
Griseofulvin
- _ weeks therapy for what?
- MOA? 2
- Administration education? 2
- 8, tinea wapitis
- MOA
- Fungistatic (inhibits fungal cell division)
- Binds to human keratin making it resistant to fungal invasion - Administration
- Taken with a fatty meal helps to increase absorption
- Take with food in general to lessen GI upset
Griseofulvin – pharmacokinetics/dynamics
- Half life?
- Aborption is enhanced by what?
- Distribution: can be distributed where? 4
- Metabolism where?
- Half life 9-24 hours
- Absorption: enhanced by ingestion of a fatty meal
- erratic
3. Distribution deposited in the -keratin layer of skin, hair, and nails -concentrates in liver, -fat, and -skeletal muscles
- Metabolism: extensive hepatic
2 formulations of griseofulvin
1. The smaller the particle size the greater the what?
- What are the two doses? 2
- The smaller the particle size the greater the bioavailability
- Dosing
-Microsize
Suspension, Grifulvin V tablets
20 to 25 mg/kg/day
-Ultramicrosize
Gris-PEG tablets
10 to 15 mg/kg/day
Contraindications and precautions with the administration of griseofulvin
5
- Liver failure
- Porphyria
- Pregnancy category X
- Use with caution if history of penicillin allergy as potential for cross reactivity
- Breast feeding not recommended
Adverse rxns: griseofulvin?
5
- SKIN: Photosensitivity, Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme
- LIVER: jaundice, elevated liver enzymes
- BONE MARROW: granulocytopenia
- NEURO: dizziness, headache, fatigue
- GI: nausea, vomiting
Drug induced lupus like syndrome
Drug interactions
- Metabolized through what?
- Beware of what interactions? 5
- Monitoring? 3
- Metabolized through
- CYP1A2, CYP2C9 and CYP 3A4 - Beware of
- warfarin,
- oral contraceptives,
- alcohol,
- barbiturates,
- cyclosporine to name a few - Monitoring:
- recommend CBC,
- renal and
- liver functions if on long term therapy (more than 8 weeks)
Terbinafine (Lamisil)
- What class is it?
- MOA?
- Systemic allylamine antifungal
- MOA
Creates ergesterol deficiency within the fungal cell wall leading to cell death
Trials comparing griseofulvin to terbinafine
1. terbinafine was superior for the treatment of infections from WHAT?
- griseofulvin was superior for the treatment of infections due to WHAT?
- Trichophyton species
- Microsporum
If you are on one drug and its not working you can switch to the other
Terbinafine – pharmacokinetics/dynamics
- Half life of what?
- Distribution where? 2
- Important drug interactions? 2
- Half life is 36 hours
- Distribution to the
- sebum and
- skin
3. Metabolized hepatically Inhibition of CYP450 enzymes Multiple drug interactions including -metoprolol and -tramadol
Most common Terbinafine side effects
3
Monitoring tests? 3
- Headache
- Diarrhea
- Elevated liver enzymes
Monitoring tests
- AST/ALT prior to initiation
- repeat if used >6 weeks - CBC
- Assess for taste and/or smell disturbance
Terbinafine for tinea capitis
- Approved for use at what age?
- Formulations available? 2
- Approved for use in ≥ 4 years of age
- Formulations available
- Granules (sprinkle on non-acidic foods)
- Tablets
Terbinafine for onychomycosis
1. Advantages? 2
- Patients who need treatment? 4
- Greater efficacy and fewer side effects than others
- Patients who need treatment
- Cosmetic reasons
- Diabetes and onychomycosis
- History of lower extremity cellulitis and ipsilateral onychomycosis
- Pain or discomfort secondary to infection
Itraconazole (Sporanox) for onychomycosis
1. BBW?
Black box warning: Negative inotropic effects have been observed following intravenous administration. Discontinue or reassess use if signs or symptoms of heart failure (HF) occur during treatment.
Contraindications – itraconazole
4
- Ventricular dysfunction
- Pregnancy
- CHF
- Concomitant use of other drugs that inhibit the CYP450 system
Itraconazole
- Half life?
- Metabolized by what?
- Better absorbed with what?
- how should you take the solution differently?
- Half life - 21 hours
- Metabolized by the liver
- Better absorbed with food (capsules) but
- take the solution on an empty stomach
Itraconazole has many drug-drug interactions
Important ones?
6
- Proton pump inhibitors,
- anxiolytics,
- pain medications,
- antiplatelet agents,
- antihypertensives,
- statins
Drug interaction checker a MUST for this drug and other azole antifungals
Adverse effects of Itraconazole?
8
- Nausea, diarrhea
- Edema
- Headache
- Rash
- Abnormal LFTs
- Heart failure
- Arrhythmia
- Hearing loss
Many others
Monitoring for Itraconazole?
3
- Baseline LFTs
- Monthly LFTs if long term therapy
- Serum concentrations
When should you draw serum concentrations of itraconazole?
-Last dose affects is how?
- Draw 2 weeks after starting therapy
2. Draw without regard to when last dose was taken
Finasteride (Propecia)
- First line therapy for what?
- MOA?
- Can also be used for the treatment of what?
- First line therapy for the treatment of androgenic alopecia in men
- 5-alpha-reductase inhibitor
- Ultimately inhibits the conversion of testosterone to dihydrotestosterone - Same as Proscar (but lower dose)
- Used for treatment of benign prostatic hypertrophy
Finasteride (Propecia): Affects PSA values
- How?
- Patients treated for ≥6 months the PSA value should be _______ when comparing to normal ranges in untreated patients
- So when should you check levels? 2
- PSA monitoring: Reduces prostate specific antigen (PSA) by ~50%
- doubled
- Baseline PSA needed, then recheck in 6 months
Finasteride (Propecia): Follow PSA levels
1. If PSA increases on this medication what should we do?
- If PSA did not change (go down about 50%) after 6 months of therapy of this drug then may indicate what?
- Finasteride efficacy?
- refer to Urology
- an increased risk for prostate cancer
- After 2 years of therapy hair counts may increase by about 25%