by Dr Charles Nansel<\/p>\n
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INTRODUCTION<\/strong><\/p>\n \u00a8Drug use during pregnancy and lactation requires special consideration because both the mother and the child are affected.<\/p>\n \u00a8Few drugs are considered safe, and drug use is generally contraindicated during pregnancy.<\/p>\n \u00a8Many pregnant or lactating women take drugs for acute or chronic disorders or habitual use of alcohol and tobacco.<\/p>\n EPIDEMIOLOGY<\/strong><\/p>\n \u00a8More than 90% of pregnant women take prescribed or non-prescribed (OTC) medicine or use social drugs (like tobaco and alcohol) or illicit drugs at some time during pregnancy.<\/p>\n \u00a8About 2-3% of all birth defects result from drugs that are taken to treat disorders or symptom<\/p>\n PRINCIPLES OF THERAPY<\/strong><\/p>\n \u00a8Give medications only when clearly indicated, weighing benefits to the mother against the risks to the fetus.<\/p>\n \u00a8Any drugs used during pregnancy should be given in the lowest effective doses and for the shortest effective time.<\/p>\n \u00a8The choice of drug should be based on the stage of pregnancy and drug information.<\/p>\n \u00a8During the first trimester, an older safe drug is preferred over a newer drug of unknown teratogenicity.<\/p>\n \u00a8Live virus vaccines (measles, mumps, polio, rubella) should be avoided because of possible harmful effects to the fetus.<\/p>\n \u00a8Inactive virus vaccines (influenza, rabies, hepatitis B) and toxoids (diphtheria, tetanus) are considered safe for use.<\/p>\n \u00a8Hyperimmune globulins can be given to pregnant women who are exposed to hepatitis B, rabies, tetanus, or varicella.<\/p>\n DRUG EFFECTS ON THE PREGNANCY<\/strong><\/p>\n \u00d8The fetus is very sensitive to any drugs, and drugs may cause teratogenicity or other adverse effects.<\/p>\n \u00d8Teratogenicity most likely occurs during the first trimester, when fetal organs are formed.<\/p>\n \u00d8During the 2nd and 3rd trimesters, adverse effects are: growth retardation, respiratory problems, or bleeding.<\/p>\n MECHANISM OF ACTION OF DRUGS IN PREGNANCY<\/strong><\/p>\n \u00a8They can act directly on the fetus, causing damage, abnormal development (leading to birth defects), or death.<\/p>\n \u00a8They can alter the function of the placenta, usually by causing blood vessels to narrow (constrict) and thus reducing the supply of oxygen and nutrients to the fetus from the mother. Sometimes the result is a baby that is underweight and underdeveloped.<\/p>\n \u00a8They can cause the muscles of the uterus to contract forcefully, indirectly injuring the fetus by reducing its blood supply or triggering preterm labour and delivery.<\/p>\n \u00a8They can also affect the fetus indirectly. For example, drugs that lower the mother’s blood pressure may reduce blood flow to the placenta and thus reduce the supply of oxygen and nutrients to the fetus.<\/p>\n TERATOGEN<\/p>\n \u00a8A teratogen is defined as any agent that results in structural or functional abnormalities in the fetus, or in the child after birth, as a consequence of maternal exposure during pregnancy<\/p>\n TERATOGENICTY<\/strong><\/p>\n \u00d8Teratogenicity is the ability of a substance to cause abnormal development of the fetus when taken by pregnant women.<\/p>\n \u00d8 Drug can affect fetus at three stages:<\/p>\n \u00a81. stage of fertilization and implantation<\/p>\n \u00a82. stage of organogenesis<\/p>\n \u00a83. stage of growth and development<\/p>\n CATEGORY<\/p>\n \u00a8The U.S. Food and Drug Administration has generated a grading system in 1974 for medications used during pregnancy. The categories are A, B, C, D, and X.<\/p>\n FDA CATEGORIES FOR THE TERATOGENIC EFECTS OF DRUGS<\/strong><\/p>\n vCategory A:<\/p>\n \u00a8Adequate studies in human demonstrate no risk (Thyroxine, magnesium sulfate)<\/p>\n vCategory B:<\/p>\n \u00a8Animal studies indicate no risk, but there are no adequate studies in human.<\/p>\n \u00a8Animal studies show adverse effects, but adequate studies in human have not demonstrated a risk (penicillin, amoxicillin, erythromycin)<\/p>\n vCategory C<\/p>\n vCategory D:<\/p>\n \u00a8There is evidence of human fetal risk, but the potential benefits to the mother may be acceptable (Aspirin, phenytoin, methotrexate)<\/p>\n vCategory X<\/p>\n \u00a8Contraindicated in pregnancy: Proven fetal risks clearly outweigh any possible benefits. drugs in this group are: Alcohol, ACE inhibitors, Lithium, Methotrexate, Valproic acid, Mifepristone, Diazole, Isotretinoin,Radioactive iodine and others.<\/p>\n COMMONLY USED DRUGS IN PREGNANCY AND THEIR CATEGORIES<\/strong><\/li>\n \u00a8NAUSEA & VOMITING: metoclopramide, ondensetron, meclizine [catB].<\/p>\n \u00a8ANTIDIARRHEAL: loperamide [cat B].<\/p>\n \u00a8HEARTBURN &DYSPEPSIA: Non absorbable antacid like aluminium hydroxide [catB], H2 blockers [cat B], ALL PPIS-catB except Omeprazole [cat C].<\/li>\n \u00a8DRUGS FOR HYPERTENTION:<\/p>\n \u00fcMethyldopa [catB].<\/p>\n \u00fcBeta blockers[cat C] like atenolol, labetolol & acebutolol.<\/p>\n \u00fcHypertensive emergencies- hydralazine[cat C].<\/p>\n \u00fcACE inhibitors\u00a0 [cat D]-contraindicated.<\/p>\n \u00fcDiuretics: furosemide-cat C, Thiazide-cat D, Sipronolactone-cat B.<\/li>\n \u00a8Causes seal-like limbs and other defects<\/p>\n \u00d8Warfarin (<\/b>Wafrin<\/b>) \u2013<\/b><\/p>\n \u00a8Causes multiple birth defects<\/p>\n \u00d8Simvastatin (<\/b>Avastin<\/b>)and other statins \u2013<\/p>\n \u00a8Cholesterol<\/b> is needed for fetal growth and its reduction by statins could harm the fetus<\/p>\n \u00d8Oral contraceptives-<\/b><\/p>\n \u00a8Can cause birth defects.<\/li>\n \u00a8Acetylsalicylate,<\/b> a common ingredient in many OTC painkillers, may make a pregnancy last longer and may cause severe bleeding before and after delivery. High doses in the last few weeks cause premature closure of ductus arteriosus, persistent pulmonary hypertension and kernicterus in newborn.<\/p>\n \u00d8Vitamin A and its derivatives <\/b><\/p>\n \u00a8can cause birth defects.<\/p>\n CONCLUSION<\/strong>\u00a8If \u201csafe use of a drug in pregnancy has not been established, It should not be administered to woman of childbearing age unless in opinion of treating physician, expected benefits to patient markedly outweigh possible hazard to child or fetus\u201d<\/p>\n \u00a8Always consider risk of untreated maternal condition.<\/li>\n \u00a8Lippincott illustrated Reviews: Pharmacology 6th Edition.<\/p>\n \u00a8Center for disease control and national birth defects prevention network(NBDPN). Preventing birth defects.available at http:\/\/www.nbdpn.org\/current\/2008pd\/prevbdbroch.pdf<\/a><\/p>\n\n
\nPREGNANCY AND SIDE EFFECT<\/strong><\/li>\n