Pregnancy Categories
The Food and Drug Administration (FDA) created the following rating system in 1979 to categorize the potential risk to the fetus for a given drug.
Category A: Controlled human studies have demonstrated no fetal risk
Category B: Animal studies indicate no fetal risk, but no human studies, OR adverse effects in animals , but not in well- controlled human studies
Category C: No adequate human or animal studies, OR adverse fetal effects in animal studies, but no available human data.
Category D: Evidence of fetal risk, but benefits outweigh risks.
Category X: Evidence of fetal risk. Risks outweigh any benefits.
Unfortunately this system oversimplifies the issues relevant to prescribing a medication to a pregnant patient. For example, the FDA system does not adequately address the risk of not treating a disease versus the risks of the medication, and there is a tendency to assume that a category B drug is safer for human use than a category C drug when there may be no human studies available to support the assumption. In addition the system is not easy to apply to combination prescription drugs with many active ingredients and the potential for drug interactions. Despite its shortcomings the FDA rating system (and others like it) will most likely continue to be used as a rapid "first screen" on the the potential risk to the fetus for a given drug.
The U.S. Food and Drug Administration (FDA) has recommended the elimination of the current pregnancy categories A, B, C, D, and X. Instead the FDA has proposed that the pregnancy and lactation subsections of labeling should include include a risk summary, which summarizes the risks of the medicine to the developing baby (fetus) or breast-feeding infant, and a discussion of the data supporting that summary [1] .
Until this labeling change becomes common practice:
Suggestions for Using Medications in Pregnancy:
When possible:
The following sites contain referenced information and useful summaries:
Drugsafetysite.com
LactMed
1. Pregnancy & Lactation Labeling. U.S. Department of Health & Human Services 10/27/2009 .Accesssed 1/27/09
Category A: Controlled human studies have demonstrated no fetal risk
Category B: Animal studies indicate no fetal risk, but no human studies, OR adverse effects in animals , but not in well- controlled human studies
Category C: No adequate human or animal studies, OR adverse fetal effects in animal studies, but no available human data.
Category D: Evidence of fetal risk, but benefits outweigh risks.
Category X: Evidence of fetal risk. Risks outweigh any benefits.
Unfortunately this system oversimplifies the issues relevant to prescribing a medication to a pregnant patient. For example, the FDA system does not adequately address the risk of not treating a disease versus the risks of the medication, and there is a tendency to assume that a category B drug is safer for human use than a category C drug when there may be no human studies available to support the assumption. In addition the system is not easy to apply to combination prescription drugs with many active ingredients and the potential for drug interactions. Despite its shortcomings the FDA rating system (and others like it) will most likely continue to be used as a rapid "first screen" on the the potential risk to the fetus for a given drug.
The U.S. Food and Drug Administration (FDA) has recommended the elimination of the current pregnancy categories A, B, C, D, and X. Instead the FDA has proposed that the pregnancy and lactation subsections of labeling should include include a risk summary, which summarizes the risks of the medicine to the developing baby (fetus) or breast-feeding infant, and a discussion of the data supporting that summary [1] .
Until this labeling change becomes common practice:
Suggestions for Using Medications in Pregnancy:
When possible:
- Avoid starting a medication during the first trimester.
- Use a medication with a proven track record in human pregnancy.
- Avoid using more than one medication.
- Use the lowest dose of medicine that works for you.
- Avoid the use of over-the counter drugs that might interact with prescription medications.
The following sites contain referenced information and useful summaries:
1. Pregnancy & Lactation Labeling. U.S. Department of Health & Human Services 10/27/2009 .Accesssed 1/27/09
posted by Peri1 at
3:39 PM
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