1. Pharmacology-4 PHL 425
Eighth Lecture By Abdelkader Ashour, Ph.D. Phone:

2. Anti-Acne Drugs, Examples
The majority of acne patients can be treated with topical medications of three types: benzoyl peroxide products, retinoids and antibiotics. Each has distinct advantages, and concurrent use of these agents may have synergistic effects
Topical benzoyl peroxide has both bactericidal and comedolytic activities
This agent is particularly useful because of its bactericidal nature, and frequent use inhibits the development of bacterial resistance
Irritation evidenced by erythema and scaling is the most significant side effect; skin hypopigmentation and bleaching of clothing may also occur
The topical retinoids (tretinoin, adapalene, tazarotene) normalize keratinocyte differentiation, decreasing the "stickiness" of the epidermal cells lining the follicular lumen. This allows the keratin plug to be expelled, thus preventing formation of comedones
All forms should be introduced gradually, to decrease the likelihood of adverse effects such as drying, irritation, or sun sensitivity. Daily therapy can usually be tolerated after several weeks; these agents are generally not used more than once a day
Oral isotretinoin is the most effective drug available for the treatment of acne. It directly suppresses sebaceous gland activity leading to significant reduction in sebaceous lipogenesis, normalizes the pattern of keratinization within the sebaceous gland follicle, inhibits inflammation, and – in a secondary manner – reduces growth of P. acnes. It is most active in the treatment of severe recalcitrant nodulocystic acne and in the prevention of acne scarring

3. Anti-Acne Drugs, Examples
Topical antibiotics including 2% erythromycin, 1% clindamycin, or a combination of 3% erythromycin and 5% benzoyl peroxide may be used in patients with an inflammatory component
These agents decrease colonization of the skin by P. acnes and may also inhibit neutrophil chemotaxis. However, resistant P. acnes has been documented
For this reason, monotherapy with topical or systemic antibiotics is discouraged. The concurrent use of topical benzoyl peroxide has been shown to inhibit and decrease resistance
Individuals with sensitive skin present a special therapeutic challenge and may benefit from sulfacetamide products or azelaic acid cream, which may also decrease postinflammatory hyperpigmentation
Azelaic acid has comedolytic and antibacterial properties and may be synergistic with retinoids
Oral antibiotics (e.g., tetracycline, minocycline, doxycycline, erythromycin) can be used when wide distribution of lesions makes topical therapy impractical

4. Anti-Warts Drugs

5. Anti-Warts Drugs, Introduction
Cutaneous warts are benign epidermal proliferations caused by human papillomavirus (HPV) infection
Papillomaviruses comprise a family of viruses that are host-species specific. Thus, HPV causes disease only in humans, infecting epithelial tissues and mucous membranes
Cutaneous warts are one of the most common skin conditions affecting children
Transmission of warts occurs from direct person-to-person contact or indirectly by fomites
Swimming pools and bathrooms are common areas for the spread of warts if the skin is macerated and touches rough surfaces
Once HPV has infected the skin, autoinoculation can occur by scratching, shaving or traumatizing the skin
Previously infected patients have a higher risk for development of new warts than those never infected
Nongenital warts occur in 7% to 10% of the general population, with the incidence peaking between the ages of 12 and 16 years
Warts occur equally in both sexes and are among the three most common dermatoses treated
Owing to natural immunity, approximately 23% of warts regress spontaneously within 2 months, 30% within 3 months and 65% to 78% within 2 years
The rate of clearance is influenced by factors such as viral type, host immune status, extent and duration of warts

6. Anti-Warts Drugs, Introduction
Verruca vulgaris (common warts) are hyperkeratotic, exophytic and dome-shaped papules or nodules especially located on fingers, hands, knees, elbows or any other sites of trauma. Generally, they are asymptomatic but sometimes cause mild pain
The clinical picture of cutaneous warts differs by specific location on the body:
Plane or flat warts are smooth flat topped papules with minimal scaling and only slight elevation, most often on the face. They are more common in children and young adults. They generally cause no symptoms but can be difficult to treat
Plantar warts are warts on the sole of the foot
They can be painful due to their callused, endophytic papules that have deeply penetrating sloping sides and a central depression
Numerous coalesced warts on the plantar surface will form a tile-like pattern known as mosaic warts. As with other plantar warts, they are often tender

7. Anti-Warts Drugs, Introduction
Filiform warts are long, frondlike growths usually on the eyelids, face, neck, or lips. They are usually asymptomatic. This morphologically distinct variant of the common wart is benign and easy to treat
Periungual warts appear as thickened, fissured cauliflower-like skin around the nail plate. Patients frequently lose the cuticle, and are susceptible to paronychia. These warts are more common in patients who bite their nails
Anogenital warts occur in the perineum and on the genitalia or in the genital tract and are one of the most common sexually transmitted diseases. They are generally asymptomatic
Although > 90% of anogenital warts resolve within 2 years, persistent infection with high-risk HPV subtypes is the main cause of cervical cancer

8. Treatment of Warts
The American Academy of Dermatology developed criteria for the indications for wart treatment including:
the patient’s desire for therapy
symptoms of pain, bleeding, itching or burning
disabling or disfiguring lesions
large numbers or large sizes of lesions
the patient’s desire to prevent the spread of warts to unblemished skin of self or others
an immunocompromised condition
Anogenital warts should receive special consideration and warrant vigilance for other sexually transmitted diseases
Extragenital warts in people who are immunocompetant are harmless and usually resolve spontaneously within months or years owing to natural immunity
In view of this, a policy of not treating them is often advised. However there is considerable social issues associated with warts on the face and hands, and they can be painful on the soles of the feet and near the nails. Therefore, many patients request treatment for their warts

9. Treatment of Warts, contd.
Salicylic acid (SA) is a first-line therapy for warts
It is a keratolytic therapy with a mechanism of action that slowly destroys virus-infected epidermis and may cause an immune response from the mild irritation caused by the salicylic acid
It is prepared in concentrations from 10% to 70%.
Over-the-counter preparations are available as 17% SA combined in a base of flexible collodion or as a 40% salicylic acid plaster patch
The advantages of over-the-counter SA include convenience, minimal expense, negligible pain and reasonable effectiveness
Disadvantages are that results require weeks to months of treatment, and the patient must strictly adhere to instructions
Side effects can include occasional contact dermatitis due to colophony in the collodion base. There is also a potential risk of systemic toxicity in children that can be avoided if lower concentrations or limited areas of treatment are used
Plantar warts may be more amenable to treatment with SA with occlusion than hand warts
Wart paints should not be used to treat facial warts because of severe irritation and a potential for scarring
Monotherapy with 5-fluorouracil, benzalkonium or cryotherapy proved no more effective than SA-containing paints