Items in AFP with MESH term: Pharmaceutical Preparations
Preconception Health Care - Article
ABSTRACT: Appropriate preconception health care improves pregnancy outcomes. When started at least one month before conception, folic acid supplements can prevent neural tube defects. Targeted genetic screening and counseling should be offered on the basis of age, ethnic background, or family history. Before conception, women should be screened for human immunodeficiency virus and syphilis infection and begin treatment to prevent the transmission of disease to the fetus. Immunizations against hepatitis B, rubella, and varicella should be completed, if needed. Women should be counseled on ways to prevent infection with toxoplasmosis, cytomegalovirus, and parvovirus B19. Environmental toxins such as cigarette smoke, alcohol, and street drugs, and chemicals such as solvents and pesticides should be avoided. In women with diabetes, it is important to optimize disease control through intensive management before pregnancy. Medications for hypertension, epilepsy, thromboembolism, depression, and anxiety should be reviewed and changed, if necessary, before the patient becomes pregnant. Counseling about exercise, obesity, nutritional deficiencies, and the overuse of vitamins A and D is beneficial. Physicians may also choose to discuss occupational and financial issues related to pregnancy and to screen patients for domestic violence.
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: Cytochrome P450 enzymes are essential for the metabolism of many medications. Although this class has more than 50 enzymes, six of them metabolize 90 percent of drugs, with the two most significant enzymes being CYP3A4 and CYP2D6. Genetic variability (polymorphism) in these enzymes may influence a patient's response to commonly prescribed drug classes, including beta blockers and antidepressants. Cytochrome P450 enzymes can be inhibited or induced by drugs, resulting in clinically significant drug-drug interactions that can cause unanticipated adverse reactions or therapeutic failures. Interactions with warfarin, antidepressants, antiepileptic drugs, and statins often involve the cytochrome P450 enzymes. Knowledge of the most important drugs metabolized by cytochrome P450 enzymes, as well as the most potent inhibiting and inducing drugs, can help minimize the possibility of adverse drug reactions and interactions. Although genotype tests can determine if a patient has a specific enzyme polymorphism, it has not been determined if routine use of these tests will improve outcomes.
Genetic Factors In Drug Metabolism - Article
ABSTRACT: Patients vary widely in their response to drugs. Having an understanding of the pharmacokinetic and pharmacodynamic properties of various medications is importantwhen assessing ethnic differences in drug response. Genetic factors can account for 20 to 95 percent of patient variability. Genetic polymorphisms for many drug-metabolizing enzymes and drug targets (e.g., receptors) have been identified. Although currently limited to a few pathways, pharmacogenetic testing may enable physicians to understand why patients react differently to various drugs and to make better decisions about therapy. Ultimately, this understanding may shift the medical paradigm to highly individualized therapeutic regimens.
ABSTRACT: Chronic kidney disease affects renal drug elimination and other pharmacokinetic processes involved in drug disposition (e.g., absorption, drug distribution, nonrenal clearance [metabolism]). Drug dosing errors are common in patients with renal impairment and can cause adverse effects and poor outcomes. Dosages of drugs cleared renally should be adjusted according to creatinine clearance or glomerular filtration rate and should be calculated using online or electronic calculators. Recommended methods for maintenance dosing adjustments are dose reductions, lengthening the dosing interval, or both. Physicians should be familiar with commonly used medications that require dosage adjustments. Resources are available to assist in dosing decisions for patients with chronic kidney disease.
Clinically Significant Drug Interactions - Article
ABSTRACT: A large number of drugs are introduced every year, and new interactions between medications are increasingly reported. Consequently, it is no longer practical for physicians to rely on memory alone to avoid potential drug interactions. Multiple drug regimens carry the risk of adverse interactions. Precipitant drugs modify the object drug's absorption, distribution, metabolism, excretion or actual clinical effect. Nonsteroidal anti-inflammatory drugs, antibiotics and, in particular, rifampin are common precipitant drugs prescribed in primary care practice. Drugs with a narrow therapeutic range or low therapeutic index are more likely to be the objects for serious drug interactions. Object drugs in common use include warfarin, fluoroquinolones, antiepileptic drugs, oral contraceptives, cisapride and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors. Many other drugs, act as precipitants or objects, and a number of drugs act as both. Regularly updated manuals of drug interactions and CD-ROM-formatted programs are useful office references.
Medications in the Breast-Feeding Mother - Article
ABSTRACT: Prescribing medications for a breast-feeding mother requires weighing the benefits of medication use for the mother against the risk of not breast-feeding the infant or the potential risk of exposing the infant to medications. A drug that is safe for use during pregnancy may not be safe for the nursing infant. The transfer of medications into breast milk depends on a concentration gradient that allows passive diffusion of nonionized, non-protein-bound drugs. The infant's medication exposure can be limited by prescribing medications to the breast-feeding mother that are poorly absorbed orally, by avoiding breast-feeding during times of peak maternal serum drug concentration and by prescribing topical therapy when possible. Mothers of premature or otherwise compromised infants may require altered dosing to avoid drug accumulation and toxicity in these infants. The most accurate and up-to-date sources of information, including Internet resources and telephone consultations, should be used.
Evaluation of Macrocytosis - Article
ABSTRACT: Macrocytosis, generally defined as a mean corpuscular volume greater than 100 fL, is frequently encountered when a complete blood count is performed. The most common etiologies are alcoholism, vitamin B12 and folate deficiencies, and medications. History and physical examination, vitamin B12 level, reticulocyte count, and a peripheral smear are helpful in delineating the underlying cause of macrocytosis. When the peripheral smear indicates megaloblastic anemia (demonstrated by macro-ovalocytes and hyper-segmented neutrophils), vitamin B12 or folate deficiency is the most likely cause. When the peripheral smear is non-megaloblastic, the reticulocyte count helps differentiate between drug or alcohol toxicity and hemolysis or hemorrhage. Of other possible etiologies, hypothyroidism, liver disease, and primary bone marrow dysplasias (including myelodysplasia and myeloproliferative disorders) are some of the more common causes.
Maintaining a Medication List in the Chart - Improving Patient Care
Taming the Sample Closet - Feature