This section provides detailed descriptions of antidotes and other therapeutic agents used in the management of a poisoned patient. For each agent, a summary is provided of its pharmacologic effects, clinical indications, adverse effects and contraindications, use in pregnancy, dosage, available formulations, and recommended minimum stocking levels for the hospital pharmacy (for availability within 60 minutes) and emergency department (for immediate availability).
Use of antidotes in pregnancy. It is always prudent to avoid or minimize drug exposure during pregnancy, and physicians are often reluctant to use an antidote for fear of fetal harm. This reluctance, however, must be tempered with a case-by-case risk-benefit analysis of the use of the particular therapeutic agent. An acute drug overdose or poisoning during pregnancy may threaten the life of the mother as well as the life of the fetus, and the antidote or therapeutic agent, despite unknown or questionable effects on the fetus, may have a lifesaving benefit. The inherent toxicity and large body burden of the drug or toxic chemical involved in the poisoning may far exceed those of the therapeutic agent or antidote.
For most of the agents discussed in this section, little or no information is available about their use in pregnant patients. The Food and Drug Administration (FDA) has established five categories (A,B,C,D, and X) of required labeling to indicate the potential for teratogenicity (Table III–1). The distinction between categories depends mainly on the amount and reliability of animal and human data and the risk-benefit assessment for the use of a specific agent. This has led to confusion, with the misbelief that risk increases in a predictable way from Category A to Category X. Note that the categorization may also be based on anticipated chronic or repeated use and may not be relevant to a single or brief antidotal treatment.
Table III-1 FDA Pregnancy Categories for Teratogenic Effects |Favorite Table|Download (.pdf)
Table III-1 FDA Pregnancy Categories for Teratogenic Effects
FDA Pregnancy Category
Adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in the first trimester, and there is no evidence of a risk later in pregnancy. The possibility of fetal harm appears remote.
Either (1) animal reproduction studies have failed to demonstrate any adverse effect (other than a decrease in fertility) but there are no adequate and well-controlled studies in pregnant women or (2) animal studies have shown an adverse effect that has not been confirmed by adequate and well-controlled studies in pregnant women. The possibility of fetal harm is probably remote.
Either (1) animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled human studies or (2) there are no animal or human studies. The drug should be given only if the potential benefit outweighs the potential risk to the fetus.
There is positive evidence of human fetal risk based on adverse ...