dermatologic drugs

glhf

Regional variation in drug penetration

For example, the scrotum, face, axilla, and
scalp are far more permeable than the forearm
and may require less drug for equivalent effect

Concentration gradient

Increasing the concentration gradient increases
the mass of drug transferred per unit time, just
as in the case of diffusion across other barriers

Dosing schedule

As a result, the “local half-life” may be long
enough to permit once-daily application of drugs
with short systemic half-lives

For example, once-daily application of
corticosteroids appears to be just as effective as
multiple applications in many conditions

an appropriate vehicle

maximizes the ability of
the drug to penetrate the outer
layers of the skin

In addition, through their physical properties
(moistening or drying effects),vehicles may
themselves have important therapeutic effects

Occlusion

(application of a plastic wrap to hold
the drug and its vehicle in close contact with the
skin) is extremely effective in maximizing
efficacy

Bacitracin

Peptide antibiotics, active against gram
positive organisms such as streptococci,
pneumococci, and staphylococci

Bacitracin

compounded in an ointment
base alone or in combination with
neomycin, polymyxin , or both

Gramicidin

Available only for topical use, in
combination with other antibiotics such as
neomycin, polymixin, bacitracin, and
nystatin

Mupirocin

Most gram-positive aerobic bacteria, including
methicillin-resistant S. Aureus (MRSA) are
resistant

Mupirocin

Effective in the treatment of impetigo caused by
S. aureus and group A beta hemolytic
streptococci

Retapamulin

A semisynthetic pleromutilin derivative effective
in the treatment of uncomplicated superficial
skin infection caused by group A beta hemolytic
streptococci and S. aureus, excluding MRSA

Polymyxin B sulfate

peptide antibiotic effective against gramnegative organisms, including Pseudomonas
aeruginosa, Escherichia coli, Enterobacter, and
klebsiella

Polymyxin B sulfate

Polymyxin B sulfate

Neomycin and gentamycin

Are aminoglycoside antibiotics active against
gram-negative organisms, including E coli,
proteus, klebsiella, and Enterobacte

Gentamicin

generally shows greater activity
against P. aeruginosa than neomycin

gentamicin

more active against
staphylococci and group A beta hemolytic
streptococci

Clindamycin

Has in vitro activity against
Propionibacterium acnes

Clindamycin

hydroalcoholic vehicle and foam
formulation (Evoclin) may cause drying
and irritation of the skin, with complaints
of burning and stinging

Erythromycin

Mechanism of action of topical
erythromycin in inflammatory acne
vulgaris is unknown\one of the possible complications of topical therapy is the development of antibiotic-resistant strains
of organisms, including staphylococci

Metronidazole

The drug may act as an anti-inflammatory
agent by direct effect on neutrophil
cellular function

Metronidazole

Oral metronidazole has been shown to be a carcinogen in susceptible rodent species, and topical use during pregnancy
and by nursing mothers and children is therefore not recommended

Sodium sulfacetamide

The nechanism of action is thought to be
inhibition of P acnes by competitive
inhibition of p-aminobenzoic acid
utilization

Sodium sulfacetamide

Approximately 4% of topically applied
sulfacetamide is absorbed
percutaneously, and its use is therefore
contraindicated in patients having a known
hypersensitivity to sulfonamides

Dapsone

for the treatment of acne vulgaris

Sodium sulfacetamide

Several combination with sulfur for the treatment of acne vulgaris and acne rosacea

dapsone

Application of dapsone gel followed by
benzoyl peroxide may result in a
temporary yellow discoloration of the skin
and hair

Topical azole derivatives

Activity against dermatophytes
(epidermophyton, microsporum, and Trichophyton) and yeasts, including Candida albicans and Pityrosporum orbiculare

Miconazole

Available for topical application as cream or lotion and as vaginal cream or suppositories for use in vulvovaginal candidiasis

Clotrimazole

available for topical application to the skin as a cream or lotion and as vaginal cream and tablets for use in vulvovaginal candidiasis

Econazole

Available as a cream for topical
application

Oxiconazole

Available as cream and lotion for topical use

Ketoconazole

Available as a cream for topical treatment of dermatophytosis and candidiasis and as a shampoo or foam for the treatment of seborrheic dermatitis

Sulconazole

Available as a cream or solution

Sertaconazole

• Available as cream
• Adverse local reactions to the imidazoles
may include stinging, pruritus, erythema,
and local irritation

Ciclopirox olamine

A synthetic broad-spectrum antimycotic agent with inhibitory activity against dermatophytes, candida species, and P. orbiculare

Ciclopirox olamine

Appear to inhibit the uptake of precursors of macromolecular synthesis; the site of action is probably the fungal cell
membrane

Ciclopirox olamine

Topical 8% has been approved for the treatment of mild to moderate
onchomycosis of fingernails and toenails

Ciclopirox olamine

Although well tolerated with minimal side
effects, the overall cure rates in clinical
trials are less than 12%

Allylamines: Naftifine and terbinafine

Highly active against dermatophytes but
less active against yeast

Allylamines: Naftifine and terbinafine

The activity derives from selective
inhibition of squalene epoxidase, a key enzyme for the synthesis of ergosterol

Allylamines: Naftifine and terbinafine

• Adverse reactions include local irritation, burning sensation, and erythema
• Contact with mucous membranes should be avoided

Butenafine

Inhibits the epoxidation of squalene, thus
blocking the synthesis of ergosterol, an
essential component of fungal cell
membranes

treatment for superficial dermatophytosis

Tolnaftate

• Synthetic antifungal compound that is
effective topically against dermatophyte
infections caused by epidermophyton,
microsporum, and Trichophyton
• It is also active against P. orbiculare but
not against candida

Nystatin and Amphotericin B

Useful in the topical therapy of C. albicans infections but ineffective against dermatophytes

Nystatin

Limited to topical treatment for cutaneous
and mucosal candida infections because
of its narrow spectrum and negligible
absorption from the gastrointestinal tract
following oral administration

Amphotericin B

Has a broader antifungal spectrum and is used intravenously in the treatment of many systemic mycoses and to a lesser extent in the treatment of cutaneous candida infections

fluconazole and itraconazole

Azole derivatives currently available for oral treatment of candida and dermatophyte infections

Tinea versicolor

responsive to short courses
of oral azoles

contraindicated

Administration of the oral azoles with midazolam, trizolam, or HMG-CoA inhibitors is _____

Griseofulvin

▪ Effective orally against dermatophyte infections
caused by epidermophyton, microsporum, and
Trichophyton

▪ It is ineffective against Candida and P. orbiculare

▪ Most effective in treating tinea infections of the
scalp and glabrous (nonhairy)skin

▪ Adverse effects seen with griseofulvin therapy
include headaches, nausea, vomiting, diarrhea,
photosensitivity, peripheral neuritis, and
occasionally confusion