Which common meds put pregnant women, infants at risk?

[DrAnil]

 Anesthetics and sedatives

In general, there are no contraindications to the careful use of lidocaine with epinephrine or prilocaine in pregnant patients, although all local anesthetics used in dentistry can cross the placental barrier, Drs. Donaldson and Goodchild noted. However, while lidocaine and prilocaine are considered risk factor B, articaine, bupivacaine, and mepivacaine are all listed as risk factor C.

Most topical anesthetics used in dentistry also are listed as risk factor C, with the exception of lidocaine, which is risk factor B. Drs. Donaldson and Goodchild recommend that practitioners use benzocaine and tetracaine preparations with caution in pregnant women.

Benzodiazepines are considered quite risky for use by pregnant or breast-feeding women and their babies. The effects of using these drugs during pregnancy may lead to fetal abortion, malformations, intrauterine growth retardation, functional deficits, carcinogenesis, and mutagenesis, with the greatest risks occurring between two and eight weeks after conception. In fact, the FDA lists these medications — such as alprazolam (Xanax), diazepam (Valium), lorazepam (Ativan), midazolam (Versed), and triazolam (Halcion) — as risk factor D/X.

Two nonbenzodiazepines — zaleplon and zolpidem — are listed as risk factor C; "if a pregnant or breast-feeding patient requires an oral sedative to help her relax throughout her dental appointment, either of these agents would be preferable to the benzodiazepines," the authors wrote.

Emergency medicines

Of all the emergency medicines one might encounter in the dental office, albuterol for the treatment of asthma or other acute bronchospasms is likely the most common. Even so, albuterol is listed by the FDA as a pregnancy risk factor C, and researchers have observed an increase in the risk of congenital malformation association with the use of this drug during pregnancy.

However, because pregnant women with untreated asthma are at much higher risk of experiencing adverse pregnancy outcomes, "In an emergency situation, the benefits to the mother exceed the risk to the fetus, and this medication needs to be administered," Drs. Donaldson and Goodchild wrote.

Similar guidelines apply to several other emergency medications, they added, including epinephrine, naloxone, flumazenil, and nitroglycerin.

Breast-feeding exceptions

With the increase in the rate of breast-feeding, more patients are inquiring about the safety and potential toxicity of drugs and chemicals that may be excreted in breast milk, Drs. Donaldson and Goodchild noted.

For most drugs, the infant is exposed to a much higher concentration during pregnancy than during lactation, so if a drug is considered acceptable for using during pregnancy, it is usually reasonable to continue its use during breast-feeding, they added.

"However, there are exceptions," they emphasized.

For example, while ibuprofen and other analgesics have been found to be safe to use when breast-feeding, daily doses of more than 100 mg of aspirin should be avoided because of the associated risk of platelet dysfunction and Reye’s syndrome. With regard to narcotics, codeine is considered the safest to use while breast-feeding, according to the American Academy of Pediatrics (AAP), while hydrocodone and oxycodone carry a higher risk of causing sedation and respiratory depression in the infant.

Similar cautions apply to the use of certain antibiotics by women who are breast-feeding. All tetracyclines, including doxycycline, are excreted in breast milk, and the manufacturers of these products do not recommend taking these medications while breast-feeding to avoid potential tooth staining. The manufacturer of clarithromycin also recommends that caution be exercised when administering this antibiotic to breast-feeding women.

All other antibiotics commonly used in dentistry — amoxicillin, azithromycin, cephalexin, clindamycin, erythromycin, metronidazole, and penicillin — are considered by the AAP to be compatible with breast-feeding, with the exception of metronidazole, according to Drs. Donaldson and Goodrich. They also recommend using erythromycin with caution "as this drug is concentrated in human milk and there are documented cases of pyloric stenosis being induced in the breast-fed newborn."

With regard to anesthetics, lidocaine (with epinephrine) and prilocaine are both considered compatible with breast-feeding, according to the AAP, even in doses exceeding the maximum allowed in humans. However, articaine is not considered compatible with breast-feeding. While no studies describing the use of epinephrine during human lactation have been published, "because of its short half-life, it is unlikely that epinephrine distributes into breast milk," Dr. Donaldson and Goodchild wrote.

Similar to the recommendations involving the use of benzodiazepines by pregnant women, the AAP does not consider most benzodiazepines to be compatible with breast-feeding. However, the pump-and-discard method sometimes used for short-acting benzodiazepines such as midazolam and triazolam has been successful for some patients, the authors noted.

"Infant exposure is reduced if breast-feeding is avoided during times when the mother receives sedative medications," they wrote. "However, because relatively small amounts of the drug are excreted into breast milk, some mothers may opt to continue nursing after weighing the benefits of breast-feeding against the potential risk to the infant."

In the long run, "A trusting, open relationship between the dentist and patient is of vital importance to optimize the mother’s treatment during her pregnancy," the authors concluded. "In particular, dentists should help pregnant or breast-feeding patients understand all of the risks and benefits before they use any prescribed medication."