IBCLC - Certification Pharmacology and Toxicology Questions and Answers

Question 1

A breastfeeding mother of a 3-week-old infant is diagnosed with mastitis and prescribed dicloxacillin. She is concerned about the medication's safety for her infant. What is the most appropriate information for the IBCLC to provide?

Accepted Answer

Reassure her that dicloxacillin is generally considered compatible with breastfeeding and to continue nursing frequently, as this helps resolve the mastitis.

Answer

Dicloxacillin is a penicillin-class antibiotic commonly used for mastitis and is considered safe for use during lactation. It has very low transfer into breast milk, and the Relative Infant Dose (RID) is far below the level of concern. Continuing to breastfeed frequently is a critical component of mastitis treatment, as it helps to drain the breast and resolve the infection. Unnecessarily interrupting breastfeeding can worsen the condition.

Question 2

A mother who is breastfeeding her 4-month-old infant reports a sudden and significant decrease in her milk supply. She mentions she recently started taking an over-the-counter medication for cold symptoms. Which of the following active ingredients is the MOST likely cause of her reduced milk production?

Accepted Answer

Pseudoephedrine

Answer

Pseudoephedrine, a common decongestant, is known to decrease milk supply, sometimes significantly, by reducing serum prolactin levels. The other medications listed—guaifenesin (an expectorant), dextromethorphan (a cough suppressant), and acetaminophen (an analgesic)—are not typically associated with a reduction in milk supply and are generally considered compatible with breastfeeding.

Question 3

When evaluating a medication's safety for a breastfed infant, the Relative Infant Dose (RID) is a key parameter. What does the RID represent?

Accepted Answer

The infant's dose via milk (in mg/kg/day) as a percentage of the mother's dose (in mg/kg/day).

Answer

The Relative Infant Dose (RID) is the standard metric for quantifying infant drug exposure through breast milk. It is calculated by dividing the infant's weight-adjusted daily dose from milk by the mother's weight-adjusted daily dose and is expressed as a percentage. An RID of less than 10% is generally considered acceptable for most medications.

Question 4

A client with postpartum depression is breastfeeding her 6-week-old infant. Her physician is considering prescribing a selective serotonin reuptake inhibitor (SSRI). Which of the following SSRIs is generally preferred for lactating individuals due to its low transfer into breast milk and extensive safety data?

Accepted Answer

Sertraline

Answer

Sertraline is widely considered a preferred SSRI for use during lactation. It has low passage into breast milk, a relatively short half-life, and infant serum levels are typically low or undetectable. While paroxetine also has low milk transfer, sertraline often has more extensive data supporting its use. Fluoxetine has a very long half-life and an active metabolite, which can lead to accumulation in the infant.

Question 5

A mother reports daily use of cannabis (marijuana) and wants to know if it is safe to continue breastfeeding her 2-month-old infant. Which of the following statements provides the most accurate information?

Accepted Answer

THC is fat-soluble, concentrates in breast milk, and has a very long half-life, posing potential risks to infant neurodevelopment.

Answer

The primary psychoactive component of cannabis, THC, is highly lipid-soluble, which causes it to concentrate in breast milk at levels higher than in the mother's plasma. It is also eliminated very slowly from the body and milk, with a half-life that can be days or even weeks, making a "pump and dump" strategy ineffective. Major health organizations recommend abstaining from cannabis during lactation due to concerns about potential long-term effects on infant neurodevelopment.

IBCLC - Certification Exam Practice Test

IBCLC - Certification Exam Practice Test

IBCLC - Certification Pharmacology and Toxicology Questions and Answers