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Biomedical subjects

Sandra R Knowles

Publications and source records attributed to Sandra R Knowles.

24 records · Page 2Linked to original sources
PubMed2003

Drug eruptions: approaching the diagnosis of drug-induced skin diseases.

Adverse drug reactions are a major problem in drug therapy, and cutaneous drug reactions account for a large proportion of all adverse drug reactions. Cutaneous drug reactions are also a challenging diagnostic problem since they can mimic a large variety of skin diseases, including viral exanthema, collagen vascular disease, neoplasia, bacterial infection, psoriasis, and autoimmune blistering disease, among others. Furthermore, determining that a particular medication caused an eruption is often difficult when the patient is taking multiple drugs. In this review, we will describe and illustrate a thoughtful, comprehensive, and clinical approach to the diagnosis and management of adverse cutaneous drug reactions. A morphologic approach to drug eruption includes those that are classified as maculopapular, urticarial, blistering or pustular with or without systemic manifestations. Exanthematous drug eruptions, drug hypersensitivity syndrome, urticaria and angioedema, serum sickness-like reactions, fixed drug eruptions, drug-induced autoimmune blistering diseases, Stevens-Johnson syndrome, toxic epidermal necrolysis, drug-induced acne, acute generalized exanthematous pustulosis, lichenoid drug eruptions and photosensitivity eruptions will be discussed.

Adverse Drug Reaction Reporting Systems↗
PubMed2002

Efavirenz-induced skin eruption and successful desensitization.

OBJECTIVE: To report a patient with efavirenz-induced hypersensitivity syndrome reaction who was successfully desensitized to efavirenz. CASE SUMMARY: A 37-year-old HIV-positive white man was placed on efavirenz, amprenavir, stavudine, lamivudine, and didanosine due to virologic failure with a previous regimen. Eight days into treatment, the patient developed a generalized rash and all medication was discontinued. Two weeks later, he was started on efavirenz, stavudine, didanosine, lamivudine, and lopinavir. The next morning, he awoke with red, itchy skin. All of the medications were discontinued. At the HIV Drug Safety Clinic, the patient was successfully restarted on amprenavir, stavudine, didanosine, lamivudine, and lopinavir. A 14-day desensitization to efavirenz was also undertaken; on day 12 of the desensitization, he once again developed a rash. He was treated symptomatically, and the desensitization protocol was extended. Sixteen months following the successful desensitization, he is tolerating full-dose efavirenz in combination with the other antiretroviral agents. DISCUSSION: The incidence of efavirenz-induced hypersensitivity ranges between 10% and 34%. Generally, an erythematous, maculopapular rash with or without fever develops 1-3 weeks after the initiation of therapy. In many patients without systemic manifestations, an attempt should be made to continue therapy and treat the rash symptomatically. If this fails, desensitization with the implicated drug can be tried. CONCLUSIONS: A history of antiretroviral-induced hypersensitivity reactions often limits the choices of medications that can be used in subsequent treatment regimens. Desensitization may allow for the continued use of previously restricted medications.

Adult↗
PubMed2002

Skin eruption following the use of two Chinese herbal preparations: a case report.

OBJECTIVE: To describe a patient who developed a widespread skin eruption following the use of two Chinese herbal medications, Fang Feng Tong Sheng Wan and Bi Yan Pian. CASE SUMMARY: A 34-year-old man developed widespread erythematous papules that coalesced into plaques after five days of therapy with two Chinese herbal preparations. There was no lymphadenopathy or hepatosplenomegaly, and the patient denied any fever, chills or malaise. The skin biopsy was compatible with a drug eruption. When the patient's oral medications, including the herbal medications, were discontinued, the skin eruption resolved over the next few weeks. All of the regular long term medications were restarted without any sequalae. DISCUSSION: This case, once again, emphasizes that, although herbal medications are marketed as natural products, these products can be associated with adverse drug effects. Other adverse effects that have been implicated with the use of Chinese herbal medications include interstitial fibrosis, renal failure, liver toxicity and severe dermatitis. In addition, there are several cases of adulteration of Chinese herbal products with synthetic medications. CONCLUSION: Although rare, Chinese herbal medications can be associated with serious adverse effects. Clinicians should question patients about the use of herbal products whenever an adverse drug effect is suspected.

Adult↗
PubMed2002

Confirming false adverse reactions to drugs by performing individualized, randomized trials.

One-patient, randomized, double-blind, controlled trials (N-of-1 RCTs) have traditionally been used to assess the efficacy of treatment. At the Drug Safety Clinic, Toronto, this methodology is used to evaluate adverse effects related to medication use, specifically when the symptoms are vague and are in response to more than one medication. Two patients are described with histories of drug allergies to multiple medications; as well, guidelines for conducting N-of-1 trials are summarized. The first patient had a history of prolonged periorbital and generalized weakness lasting up to one week after exposure to a variety of drugs. Because of the ambiguous results of local anesthetic skin testing, an N-of-1 trial was performed using lidocaine without preservative. Two short-lived episodes of blepharospasm and lethargy were observed with placebo; no subjective or objective reaction occurred with active drug. The second patient had a history of prolonged weakness and drowsiness after exposure to many medications; she had been told that she was allergic to all drugs with a benzene ring. During the first N-of-1 trial, generalized weakness was observed with 10 mg of dimenhydrinate and all four placebo doses. During the second N-of-1 challenge using codeine, no unwarranted reactions occurred with either active or placebo drug. Traditional testing of these patients to disprove the clinical symptoms is often difficult because of the anxiety level associated with the patients' past experiences. N-of-1 trials provide a useful alternative for the management of patients with nonspecific symptomatology attributed to drug ingestion.

Administration, Oral↗