Items in AFP with MESH term: Drug Interactions
Treating Onychomycosis - Article
ABSTRACT: Onychomycosis accounts for one third of fungal skin infections. Because only about one half of nail dystrophies are caused by fungus, the diagnosis should be confirmed by potassium hydroxide preparation, culture or histology before treatment is started. Newer, more effective antifungal agents have made treating onychomycosis easier. Terbinafine and itraconazole are the therapeutic agents of choice. Although the U.S. Food and Drug Administration has not labeled fluconazole for the treatment of onychomycosis, early efficacy data are promising. Continuous oral terbinafine therapy is most effective against dermatophytes, which are responsible for the majority of onychomycosis cases. Intermittent pulse dosing with itraconazole is as safe and effective as short-term continuous therapy but more economical and convenient. With careful monitoring, patients treated with the newer antifungal agents have a good chance of achieving relief from onychomycosis and its complications.
Treatment of Hypothyroidism - Article
ABSTRACT: Thyroid disease affects up to 0.5 percent of the population of the United States. Its prevalence is higher in women and the elderly. The management of hypothyroidism focuses on ensuring that patients receive appropriate thyroid hormone replacement therapy and monitoring their response. Hormone replacement should be initiated in a low dosage, especially in the elderly and in patients prone to cardiac problems. The dosage should be increased gradually, and laboratory values should be monitored six to eight weeks after any dosage change. Once a stable dosage is achieved, annual monitoring of the thyroid-stimulating hormone (TSH) level is probably unnecessary, except in older patients. After full replacement of thyroxine (T4) using levothyroxine, the addition of triiodothyronine (T3) in a low dosage may be beneficial in some patients who continue to have mood or memory problems. The management of patients with subclinical hypothyroidism (a high TSH in the presence of normal free T4 and T3 levels) remains controversial. In these patients, physicians should weigh the benefits of replacement (e.g., improved cardiac function) against problems that can accompany the excessive use of levothyroxine (e.g., osteoporosis).
Quinolones: A Comprehensive Review - Article
ABSTRACT: With the recent introduction of agents such as gatifloxacin and moxifloxacin, the traditional gram-negative coverage of fluoroquinolones has been expanded to include specific gram-positive organisms. Clinical applications beyond genitourinary tract infections include upper and lower respiratory infections, gastrointestinal infections, gynecologic infections, sexually transmitted diseases, and some skin and soft tissue infections. Most quinolones have excellent oral bioavailability, with serum drug concentrations equivalent to intravenous administration. Quinolones have few adverse effects, most notably nausea, headache, dizziness, and confusion. Less common but more serious adverse events include prolongation of the corrected QT interval, phototoxicity, liver enzyme abnormalities, arthropathy, and cartilage and tendon abnormalities. The new fluoroquinolones are rarely first-line agents and should be employed judiciously. Inappropriate use of agents from this important class of antibiotics will likely worsen current problems with antibiotic resistance. Applications of fluoroquinolones in biologic warfare are also discussed.
Proton Pump Inhibitors: An Update - Article
ABSTRACT: Since their introduction in the late 1980s, proton pump inhibitors have demonstrated gastric acid suppression superior to that of histamine H2-receptor blockers. Proton pump inhibitors have enabled improved treatment of various acid-peptic disorders, including gastroesophageal reflux disease, peptic ulcer disease, and nonsteroidal antiinflammatory drug-induced gastropathy. Proton pump inhibitors have minimal side effects and few significant drug interactions, and they are generally considered safe for long-term treatment. The proton pump inhibitors omeprazole, lansoprazole, rabeprazole, and the recently approved esomeprazole appear to have similar efficacy.
ABSTRACT: Older Americans comprise 13 percent of the population, but they consume an average of 30 percent of all prescription drugs. Every day, physicians are faced with issues surrounding appropriate prescribing to older patients. Polypharmacy, use of supplements, adherence issues, and the potential for adverse drug events all pose challenges to effective prescribing. Knowledge of the interplay between aging physiology, chronic diseases, and drugs will help the physician avoid potential adverse drug events as well as drug-drug and drug-disease interactions. Evidence is now available showing that older patients may be underprescribed useful drugs, including aspirin for secondary prevention in high-risk patients, beta blockers following myocardial infarction, and warfarin for nonvalvular atrial fibrillation. There is also evidence that many older adults receive medications that could potentially cause more harm than good. Finding the right balance between too few and too many drugs will help ensure increased longevity, improved overall health, and enhanced functioning and quality of life for the aging population.
ABSTRACT: Antiretroviral regimens are complicated and difficult for patients to follow, and they can have serious side effects, such as osteonecrosis and bone demineralization. Protease inhibitor therapy has been associated with hyperlipidemia, hyperglycemia, gastrointestinal symptoms, and body-fat distribution abnormalities. Nonnucleoside reverse transcriptase inhibitors can cause rashes and hepatotoxicity, and nucleoside reverse transcriptase inhibitors can cause lactic acidosis, hypersensitivity reactions, neuropathies, pancreatitis, anemia, and neutropenia. Malabsorption can occur if antiretroviral agents are taken improperly with regard to meals or if they are taken with certain other drugs or herbal remedies. Some commonly prescribed drugs can cause dangerous drug toxicities if they are taken by patients who are also taking certain antiretroviral medications. Suboptimal exposure to antiretrovirals because of noncompliance or malabsorption can result in viral resistance and loss of future treatment options.
ABSTRACT: Drug hypersensitivity results from interactions between a pharmacologic agent and the human immune system. These types of reactions constitute only a small subset of all adverse drug reactions. Allergic reactions to medications represent a specific class of drug hypersensitivity reactions mediated by IgE. Immune-mediated drug reactions may be discussed generally in the Gell and Coombs classification system, a widely accepted conceptual framework for understanding complex immune reactions. However, some reactions involve additional, poorly understood mechanisms that are not easily classified. Identifiable risk factors for drug hypersensitivity reactions include age, female gender, concurrent illnesses, and previous hypersensitivity to related drugs. Drug hypersensitivity is a clinical diagnosis based on available data. Laboratory testing may be useful, with skin testing providing the greatest specificity. Treatment is largely supportive and includes discontinuation of the offending medication, symptomatic treatment, and patient education. Patients with penicillin allergy should avoid carbapenems, and caution should be used in prescribing cephalosporins in these patients. Reactions to radiocontrast media can be limited by pretreatment with prednisone, diphenhydramine, and either ephedrine or a histamine H2-receptor antagonist.
ABSTRACT: Amiodarone is a potent antiarrhythmic agent that is used to treat ventricular arrhythmias and atrial fibrillation. The drug prevents the recurrence of life-threatening ventricular arrhythmias and produces a modest reduction of sudden deaths in high-risk patients. Amiodarone is more effective than sotalol or propafenone in preventing recurrent atrial fibrillation in patients for whom a rhythm-control strategy is chosen. When long-term amiodarone therapy is used, potential drug toxicity and interactions must be considered. The dosage of amiodarone should be kept at the lowest effective level. In patients who also are taking digoxin and warfarin, physicians must pay close attention to digoxin levels and prothrombin time, keeping in mind that the effects of interaction with amiodarone do not peak until seven weeks after the initiation of concomitant therapy. Laboratory studies to assess liver and thyroid function should be performed at least every six months.
Methadone Treatment for Pain States - Article
ABSTRACT: Methadone is a synthetic opioid with potent analgesic effects. Although it is associated commonly with the treatment of opioid addiction, it may be prescribed by licensed family physicians for analgesia. Methadone's unique pharmacokinetics and pharmacodynamics make it a valuable option in the management of cancer pain and other chronic pain, including neuropathic pain states. It may be an appropriate replacement for opioids when side effects have limited further dosage escalation. Metabolism of and response to methadone varies with each patient. Transition to methadone and dosage titration should be completed slowly and with frequent monitoring. Conversion should be based on the current daily oral morphine equivalent dosage. After starting methadone therapy or increasing the dosage, systemic toxicity may not become apparent for several days. Some medications alter the absorption or metabolism of methadone, and their concurrent use may require dosing adjustments. Methadone is less expensive than other sustained-release opioid formulations.
ABSTRACT: Grapefruit is a healthy addition to a well-balanced diet. However, the fruit has been shown to affect the metabolism of many medications, increasing the risk of toxicity and adverse effects. Characteristics of oral medications that may interact with grapefruit include extensive metabolism through the intestinal cytochrome P450 3A4 system, low bioavailability, and a narrow therapeutic index. Prominent medications known to interact with grapefruit include statins, antiarrhythmic agents, immunosuppressive agents, and calcium channel blockers. There are equally effective alternatives to these drug classes that do not have the potential to interact with grapefruit. These alternative drugs may be substituted if a patient experiences or is at risk of a grapefruit-drug interaction. Patients also may choose to exclude grapefruit from their diets and consume other fruits, including other types of citrus, to avoid an interaction.