Clinically significant drug interactions in dermatology

Drug interactions in dermatology: what the dermatologist should know

A drug interaction is a process by which a drug or any other substance interacts with another drug and affects its activity by increasing or decreasing its effect, causing a side effect or producing a new effect unrelated to the effect of either. Interactions may be of various types-drug-drug interactions, drug-food interactions, drug-medical condition interactions, or drug-herb interactions. Interactions may occur by single or multiple mechanisms. They may occur in vivo or in vitro (pharmaceutical reactions). In vivo interactions may be further subdivided into pharmacodynamic or pharmacokinetic reactions. Topical drug interactions which may be agonistic or antagonistic may occur between two drugs applied topically or between a topical and a systemic drug. Topical drug-food interaction (for example, grape fruit juice and cyclosporine) and drug-disease interactions (for example, topical corticosteroid and aloe vera) may also occur. It is important for the dermatologist to be aware of such interactions to avoid complications of therapy in day-to-day practice.

Systemic use of non-biologic corticosteroids in orofacial diseases

Systemic non-biologic agents have long been in clinical use in medicine - often with considerable efficacy, albeit with some adverse effects--as with all medications. With the advent of biologic agents, all of which currently are restricted to systemic use, there is a growing need to ensure which agents have the better therapeutic ratio. The non-biologic agents (NBAs) include a range of agents, most especially the corticosteroids (corticosteroids). This study reviews the corticosteroids in systemic use in management of orofacial mucocutaneous diseases; subsequent studies discuss corticosteroid-sparing agents used in the management of orofacial diseases, such as calcineurin inhibitors used to produce immunosuppression; purine synthetase inhibitors; and cytotoxic and other immunomodulatory agents.

Oral antibiotic drug interactions of clinical significance to dermatologists

Oral antibiotics are commonly prescribed by dermatologists in clinical practice. When prescribing an oral antibiotic, as with other systemic medications, it is important to consider potential interactions with other drugs, including over-the-counter medications. The most common drug interaction mechanisms that may lead to clinically significant sequelae are inhibition of GI drug absorption and alterations in drug metabolism. Tetracycline and quinolones undergo chelation interactions with many metal ions found in antacids and mineral supplements. Some macrolides, such as erythromycin, inhibit the hepatic metabolism of many other drugs, increasing the risk for toxicity. Rifampin increases the metabolism of many other drugs, thus predisposing to treatment failure. Drug interactions can only be averted if their potential is understood and recognized in advance.

Update on clinically significant drug interactions in dermatology

Although there are thousands of drug interactions (DIs) listed in computers and manuals, only about 10% are clinically significant. Equally disturbing is these systems fail to detect up to one third of all dangerous DIs. This update on clinically significant DIs is current through September 2005 and discusses systemic drugs important to dermatologists. In addition, 4 aspects of DIs are discussed that are helpful in replacing rote memory with a step-by-step, logical approach based on scientific evidence.

Cutaneous fungal infections in the elderly

Because of impaired host defenses and a favorable environment at specific anatomic sites, there is an increased prevalence of seborrheic dermatitis, mucosal and cutaneous candidiasis, tinea pedis, and onychomycosis in the geriatric population compared with other age groups. Both KOH and fungal culture are timely, convenient, and cost-effective methods of diagnosis. Sensitivity of these tests depends on proper technique for specimen collection and experience. KOH 20% with DMSO and DTM are highly recommended. Treatment should be tailored to the diagnosis and the individual patient. This includes the targeted spectrum of coverage (dermatophyte or yeast); topical versus systemic therapy; review of the patient's medication list for potential drug interactions; and likelihood of compliance. Checking baseline laboratories and routine monitoring of complete blood count and liver function tests in healthy patients, without a history of liver disease or active hepatitis, and without potential drug interactions, seems unwarranted for rare adverse events. Successful management requires adequate patient education, correction of underlying predisposing factors, and prophylactic measures against recurrence.

Progress in the understanding of the pathology and pathogenesis of cutaneous drug eruptions : implications for management

Cutaneous drug eruptions are among the most common adverse reactions to drug therapy. The etiology may reflect immunologic or nonimmunologic mechanisms, the former encompassing all of the classic Gell and Combs immune mechanisms. Cumulative and synergistic effects of drugs include those interactions of pharmacokinetic and pharmacodynamic factors reflecting the alteration by one drug of the effective serum concentration of another and the functions of drugs and their metabolites that interact to evoke cutaneous and systemic adverse reactions. Recent observations include the role of concurrent infection with lymphotropic viruses and drug effects that, through the enhancement of lymphoid blast transformation and/or lymphocyte survival and the contribution of intercurrent systemic connective tissue disease syndromes, promote enhanced lymphocyte longevity and the acquisition of progressively broadening autoantibody specificities. The latter are particularly opposite to drug-induced lupus erythematosus and to drug reactions in the setting of HIV infection. Specific common types of cutaneous drug eruptions will be discussed in this review. Successful management of cutaneous drug eruptions relies upon the prompt discontinuation of the causative medication; most drug eruptions have a good prognosis after this is accomplished. Oral or topical corticosteroids can be administered to aid in the resolution of some types of eruptions. Antihistamines or anti-inflammatory agents may also be administered for some eruptions.

Important drug interactions and reactions in dermatology

A constantly expanding pharmacological armamentarium increases the concern for serious drug interactions. This article discusses drug metabolism and how the cytochrome P-450 family facilitates drug biotransformation. Clinically significant drug interactions involving antifungal drugs, antibiotics, retinoids, and immunosuppressive agents, as well as topical anesthetics and various foods, are included.

Oral griseofulvin remains the treatment of choice for tinea capitis in children

Tinea capitis is one of the most common infections of children. The standard treatment is griseofulvin. Itraconazole and terbinafine have in large part replaced griseofulvin in the treatment of onychomycosis and, in addition to fluconazole and ketoconazole, are evolving treatments for tinea capitis. The purpose of this review is to compare the efficacy, safety, and cost of oral antifungal agents for tinea capitis. Small, open-label studies of itraconazole, terbinafine, and fluconazole have reported encouraging results, suggesting that these drugs may be effective alternatives to griseofulvin; however, in large controlled studies griseofulvin continues to exhibit greater or equal efficacy. Ketoconazole appears to be the least efficacious. All five drugs appear relatively safe, however, only griseofulvin has a long track record of safety, is Food and Drug Administration (FDA) approved for the treatment of tinea capitis in children, and has the least known drug interactions. Fluconazole is FDA approved for use in children more than 6 months of age, yet not for the treatment of tinea capitis. Oral griseofulvin and terbinafine tablets are the least expensive of the antifungal agents; griseofulvin suspension is, however, more expensive than fluconazole suspension. For the combined reasons of efficacy, safety, and cost, and a long track record of use, we feel oral griseofulvin is still the present treatment of choice for tinea capitis. Newer antifungals are currently under investigation, and their role in treating tinea capitis in children is still being defined.

HIV and AIDS in inpatient dermatology. Approach to the consultation

In the inpatient setting, the dermatologic consultant is called on to address the whole spectrum of cutaneous disease seen in HIV/AIDS patients, with severity varying from severe life-threatening to less serious conditions that dramatically affect quality of life. Rather than reviewing a "laundry list" of conditions associated with HIV/AIDS or the most severe conditions, this article aims to demonstrate a systematic approach to inpatient dermatology consultation in HIV/AIDS patients and to briefly review several common and interesting topics frequently addressed in the inpatient setting (e.g., medications issues, and phototherapy in HIV-infected patients).

Recent advances in the pathology of cutaneous drug eruptions

Cutaneous reactions to drug therapy may be of either immunologic or nonimmunologic etiology. It is important that the dermatologist and pathologist be familiar with these types of cutaneous reactions. This article discusses the clinical features, pathogenesis, and histopathology of various cutaneous drug eruptions.