Risk classification systems for drug use during pregnancy: are they a reliable source of information?

Treating common problems of the nose and throat in pregnancy: what is safe?

Although all kinds of medications should be avoided during pregnancy, the majority of pregnant women receive at least one drug and 6% of them during the high-risk period of the first trimester. The aim of the present paper is to discuss the appropriate management of rhinologic and laryngeal conditions that may be encountered during pregnancy. A literature review from Medline and database sources was carried out. Related books and written guidelines were also included. Controlled clinical trials, prospective and retrospective studies, case-control studies, laboratory studies, clinical and systematic reviews, metanalyses, and case reports were analysed. The following drugs are considered relatively safe: beta-lactam antibiotics (with dose adjustment), macrolides (although the use of erythromycin and clarithromycin carries a certain risk), clindamycin, metronidazole (better avoided in the first trimester), amphotericin-B (especially in immunocompromised situations during the second and third trimester) and acyclovir. First-line antituberculous agents isoniazid, ethambutol, pyrazinamide, and ciprofloxacine in drug-resistant tuberculosis can be also used. Non-selective NSAIDs (until the 32nd week), nasal decongestants (with caution and up to 7 days), intranasal corticosteroids, with budesonide as the treatment of choice, second generation antihistamines (cetirizine in the third trimester, or loratadine in the second and third trimester), H2 receptor antagonists (except nizatidine) and proton pump inhibitors (except omeprazole) can be used to relieve patients from the related symptoms. In cases of emergencies, epinephrine, prednisone, prednisolone, methylprednisolone, dimetindene and nebulised b(2) agonists can be used with extreme caution. By contrast, selective COX-2 inhibitors and BCG vaccination are contraindicated in pregnancy. When prescribing to a pregnant woman, the safety of the materno-foetal unit is considered paramount. Although medications are potentially hazardous, misconceptions and suboptimal treatment of the mother might be more harmful to the unborn child. Knowledge update is necessary to avoid unjustified hesitations and provide appropriate counselling and treatment for pregnant women.

Medications during pregnancy: antihypertensives and immunosuppressives

Use of prescription and nonprescription medications is common during pregnancy and is required in many women with underlying kidney disease or hypertension and in all with solid-organ allografts. Systematic assessment of drug safety during pregnancy is lacking, as are rigorous and comprehensive studies of pharmacokinetics and pharmacodynamics to guide drug selection and dosing across pregnancy. Renal and hepatic clearances of many drugs change markedly during pregnancy and pitfalls may complicate routine therapeutic monitoring of some drugs during pregnancy. However, available data and clinical experience allow reasonable strategies for selection and dosing of immunosuppressive agents in pregnant transplant recipients and of antihypertensive agents in women with mild or more severe hypertension complicating their pregnancies.

The effectiveness of Teratology Information Services (TIS)

BACKGROUND

Women and their health care providers have few reliable sources of information regarding the safety of exposures in pregnancy and lactation. Evidence-based information on these topics is provided by Teratology Information Services (TIS). Access to TIS, however, is limited in many regions, and many services have difficulty maintaining ongoing funding. The objective of this review is to highlight published reports of the effectiveness of TIS in improving maternal and neonatal health.

METHODS

A search of the Pub Med and Econ Lit databases was performed with no date restriction, using the search terms teratology, information, counseling, pregnancy, effectiveness, birth defects.

RESULTS

Information disseminated from TIS has been shown to prevent congenital malformations, unnecessary pregnancy terminations, and occupational risks. TIS support optimal nutritional supplementation in pregnancy and optimal drug therapy in pregnancy and breast-feeding. In addition, they correct misperceptions of risk and facilitate knowledge transfer and translation. TIS have the potential to provide health care cost savings.

CONCLUSIONS

TIS are vital services in supporting optimal maternal and neonatal health. A formal economic evaluation of TIS is required in order to inform resource allocation decision-making and continued funding of these services.

Safety of medications prescribed before and during early pregnancy in a cohort of 81 975 mothers from the UK General Practice Research Database

PURPOSE

To demonstrate a linkage methodology for mother and baby automated medical records, and describe frequency, type, and pregnancy risk level of medications prescribed during pregnancy in a GPRD cohort, 1991-1999.

METHODS

We linked records using a two-stage algorithm and selected pairs with > or = 7 months prenatal records and > or = 2 records in baby's first year of life. Periods of interest were: 90 days prior to a woman's earliest identified pregnancy record (Period I), and this record plus 70 days (Period II, approximate early pregnancy). Medications were classified using the British National Formulary and US Food and Drug Administration Pregnancy Risk Categories.

RESULTS

We achieved over 80% record linkage and defined a cohort of 81,975. Sixty-five per cent of mothers had > or = 1 prescription during both periods combined. Most frequent medications in Period I were anti-bacterial, contraceptive, topical steroid, and bronchodilator. In Period II, they were folic acid, anti-bacterial, antacid, and gynecological anti-infective. In Period I, 4% were FDA category A (considered safest), 34% B, and 49% C and D combined. By Period II, prescription of category A medications increased (folic acid, iron) while other categories declined. Category X medications, with potential teratogenic risk that outweighs maternal benefit, were prescribed to 5714 (7%) women in Period I, and 501 (0.6%) women in Period II (46% progesterone).

CONCLUSIONS

One in every 164 women received a category X prescription in early pregnancy. The visit when pregnancy is first medically recognized represents an opportunity to review prescribed medications in light of contraindication and/or fetal risk.

Prescription of teratogenic medications in United States ambulatory practices

PURPOSE

The purpose of this study was to identify the potentially teratogenic medications most frequently prescribed to women of childbearing age and the specialty of physicians who provide ambulatory care to women who use such medications. In addition, we evaluated rates of contraceptive counseling to explore awareness of the risks associated with teratogenic medication use.

SUBJECTS AND METHODS

The prescription of teratogenic medications and provision of contraceptive counseling on 12,681 visits made by nonpregnant women, 14 to 44 years of age, to 1880 physicians in US ambulatory practice (National Ambulatory Medical Care Survey) between 1998 and 2000 was analyzed.

RESULTS

Use of a potentially teratogenic, class D or X, medication by a woman of childbearing age is documented on 1 of every 13 visits made to US ambulatory practices. These include anxiolytics (4.1 million annual prescriptions), anticonvulsant medications (1.4 million annual prescriptions), antibiotics like doxycycline (1.4 million annual prescriptions), and statins (0.8 million annual prescriptions). Isotretinoin accounts for less than 5% of potentially teratogenic prescriptions (0.5 million annual prescriptions). Internists and family/general practitioners provide ambulatory care to 45% of women prescribed potentially teratogenic medications, psychiatrists provide ambulatory care to 20% of women prescribed potentially teratogenic medications, and dermatologists provide ambulatory care to 20% of women prescribed potentially teratogenic medications. Contraceptive counseling was provided on less than 20% of visits that documented use of a potential teratogen by a woman of childbearing age. Women using low-risk (class A or B) drugs received contraceptive counseling as frequently as women using potential teratogens (P = .24).

CONCLUSION

Potentially teratogenic medications are prescribed to millions of women of childbearing age each year. Physician awareness of the teratogenic risk associated with class D or X medications seems low.

Drug use by pregnant women and comparable non-pregnant women in The Netherlands with reference to the Australian classification system

OBJECTIVE

To describe drug use in pregnancy, and compare drug use of pregnant women with non-pregnant women with respect to possible teratogenicity.

STUDY DESIGN

A cross-sectional study based on pharmacy records from 1997 to 2001 was performed. Pregnant women and matched non-pregnant women (same physician and age) were identified. Prescriptions were set against the Australian risk classification.

RESULTS

Thirty-five percent of all prescriptions for non-pregnant women were safe in pregnancy (Australian classification A), in 14% the risk was unknown (B1, B2), 49% were potentially harmful drugs (B3, C, D, X), and in 3% no classification was available. For pregnant women these figures were 86, 3, 10 and 2%, respectively. In non-pregnant women the highest percentages of prescriptions for unsafe drugs were for psycholeptics (99% not classified as safe), psychoanaleptics (100%), anti-inflammatory/antirheumetic products (100%), antihistamines (94%), antacids/anti-ulcer drugs (81%), antiepileptics (100%), beta-blockers (100%), systemic antimycotics (100%), antiprotozoals (97%), diuretics (100%) and immunosuppressives (100%). In pregnant women this pattern was comparable, except for antihistamines (22%) and antacids/anti-ulcer drugs (3%).

CONCLUSION

We conclude that many drugs used by non-pregnant women should be avoided in pregnancy, and that pregnant women indeed do so. However, for some drug groups the available safe alternatives are limited.

Postoperative pain management in obstetric anesthesia–new challenges and solutions

The current understanding of pain processing mechanisms, the different pharmacologic drugs, and other nonpharmacologic means that can be used to manage postobstetric operation pain are reviewed.

Prescription of Hazardous Drugs During Pregnancy

BACKGROUND

Prescribing drugs to pregnant women requires the balancing of benefits and risks. Only a small proportion of drugs are known to be harmful to the fetus, but for the vast majority of drugs little evidence of fetal safety exists.

AIM

To determine the prescription pattern of potentially and clearly harmful prescription drugs during pregnancy with reference to drug safety categorisation, and to define the drug groups primarily responsible for multiple drug use during pregnancy.

STUDY DESIGN

A retrospective, register-based cohort study.

METHODS

Linkage of three nationwide registers in Finland. Data collection included prescription drugs purchased during the preconception period and each trimester in the pregnant cohort, and the corresponding time periods in the non-pregnant controls. The pregnancy safety categorisation was determined for each drug (Anatomic Therapeutic Chemical [ATC] code) by using the Swedish classification of approved medicinal products (Farmaceutiska Specialiteter i Sverige [FASS]) and if not available, the corresponding Australian (Australian Drug Evaluation Committee [ADEC]) or US categorisation (FDA). GROUPS STUDIED: Women applying for maternity support (maternal grants) during the year 1999 (n = 43 470) plus non-pregnant control women matched by age and hospital district (n = 43 470).

RESULTS

In the pregnant cohort, 20.4% of women purchased at least one drug classified as potentially harmful during pregnancy, and 3.4% purchased at least one drug classified as clearly harmful. A significant decline occurred in the number of pregnant women purchasing potentially and clearly harmful drugs during the first trimester when compared with the preconception period, and the decline continued from the first to the second trimester. In the pregnant cohort, 107 (0.2%) women purchased at least ten different drugs during pregnancy. The drugs most commonly purchased in this group were topical corticosteroids and nasal preparations.

CONCLUSION

The use of hazardous prescription drugs declines during pregnancy but prescriptions of known teratogens and the relatively frequent practice of polypharmacy in epilepsy place emphasis on the need for careful pre-pregnancy counselling. However, drug safety classifications give a very crude estimation of risk and should only be used as general guidelines when planning treatment. Risk assessment must always be made on an individual basis, and pregnant women with illnesses requiring treatment must be treated adequately.

Medications in pregnancy and lactation

Lack of information and misinformation often lead to physicians advising mothers to discontinue breastfeeding because of medication use. Also, many mothers do not adhere to their prescriptions or quit breastfeeding because of medication use. Although in both cases this cessation of breastfeeding is probably based on concern for the infant's safety, the physician may also be influenced by expediency and fear of litigation. The safest course for physicians who are treating nursing mothers is to consult reliable sources before advising discontinuation of breastfeeding. Overwhelming evidence has shown that breastfeeding is the most healthful form of nutrition for babies and should therefore be encouraged by physicians. Physicians should take the following approach to maximize safe maternal medication use for both the mother and the breastfed infant: 1. Determine if medication is necessary. 2. Choose the safest drug available, that is, one that; is safe when administered directly to infants, has a low milk:plasma ratio, has a short half-life, has a high molecular weight, has high protein binding in maternal serum, is ionized in maternal plasma, is less lipophilic. 3. Consultation with the infant's pediatrician is encouraged. 4. Advise the mother to take the medication just after she has breastfed the infant or just before the infant's longest sleep period. 5. If there is a possibility that a drug may risk the health of the infant, arrange for the monitoring of serum drug levels in the infant. Emergency physicians are often faced with the daunting task of treating a large variety of high-acuity patients, including patients who happen to be pregnant or nursing mothers. Priority, of course, needs to be given to life-saving treatment. When physicians are treating pregnant or breastfeeding patients, they need to use reliable resources to evaluate the risks and benefits of the medication for the mother and the infant. Most medications should have no effect on milk supply or on infant well-being. In most cases, treatment plans for patients should include encouragement from the emergency physician that he or she has researched the chosen medicine and that breastfeeding may safely continue.

Pregnancy and immunology: selected aspects

LEARNING OBJECTIVES

This article reviews current concepts of the immunology of pregnancy and of the diagnosis and management of certain allergic conditions in the pregnant woman: asthma, rhinitis, immunotherapy, and hereditary angioedema (HAE).

DATA SOURCES

Current texts, reviews, and individual studies were picked from the National Library of Medicine database.

RESULTS AND CONCLUSIONS

Knowledge concerning the immunologic paradox of pregnancy continues to evolve. Although the answer is not definitive, attention is being paid to the role of a Th-2 shift in the pregnant uterus. Extensive studies, both epidemiologic and therapeutic, are clarifying the influence of pregnancy on asthma and rhinitis (and vice versa) and the best methods for treatment of these conditions in the pregnant woman. A brief guideline to the handling of hereditary angioedema in pregnancy is presented.

Review of pregnancy labeling of prescription drugs: is the current system adequate to inform of risks?

Evidence-based medicine that is designed to guide benefit/risk drug therapy decisions does not exist for pregnant women. The types of studies that do exist are usually conducted in animals, which may not reflect human benefits and risks. The types of studies that do exist in humans are typically limited and, at best, may show an "association" between a particular drug therapy and an undesirable effect. This review outlines the difficulties that are associated with the assessment of the benefits/risks of drug therapy during pregnancy, the history of the Food and Drug Administration regulations for labeling prescription drugs, and the strengths and weaknesses of the current Food and Drug Administration pregnancy labeling system. Proposed changes to the current system are reviewed.