The medication requirements for avatrombopag vary among different populations, and pregnant women, children, older adults, and patients with hepatic or renal impairment require special attention. The following explains this from three aspects.

I. Use During Pregnancy and Lactation

1. Pregnancy May Harm the Fetus

Animal studies show that administration of avatrombopag during organogenesis can lead to adverse developmental outcomes. Use in pregnant women may cause fetal harm, and the potential risk should be communicated. Women of reproductive potential who are known or suspected to be pregnant should inform their doctor promptly.

2. Breastfeeding Is Not Recommended During Lactation

It is unknown whether avatrombopag passes into human milk, but the drug can be present in rat milk. Because of the potential for serious adverse reactions in a breastfed infant, breastfeeding is not recommended during treatment and for at least 2 weeks after the last dose.

3. Management for Short-Term Users

Lactating women who receive short-term treatment, such as before an invasive procedure, should interrupt breastfeeding and pump and discard breast milk during treatment and for 2 weeks after the last dose to minimize infant exposure.

II. Use in Pediatric and Older Adult Patients

1. Choose Dosage Form by Age in Pediatric Patients

Tablets are used for persistent or chronic immune thrombocytopenia in children aged 6 years and older; oral granules are used for patients aged 1 year to less than 6 years. The two dosage forms cannot be directly substituted on a milligram-to-milligram basis. If the formulation is switched, monitor platelet counts weekly until stable, then resume monthly monitoring.

2. Pay Attention to Weight Effects in Pediatric Patients

Lower body weight may be associated with higher blood drug concentrations. Pediatric patients aged 1 year to less than 6 years receiving 10 mg granules have higher exposure than adults receiving 20 mg tablets. Parents should strictly follow the prescribed dose and not adjust it on their own.

3. Older Adults Do Not Require Adjustment Based on Age Alone

The proportion of older patients in clinical studies was limited, but available data have not identified clear differences in response between older and younger patients. Older patients should still follow standard dosing principles and pay attention to concomitant medications and underlying diseases.

III. Hepatic or Renal Impairment and Drug Interactions

1. No Dose Adjustment Needed for Patients with Chronic Liver Disease

Patients with chronic liver disease do not need dose adjustment based on liver function when using avatrombopag. However, these patients have a higher risk of thrombosis, so platelet counts and signs of thromboembolism should be monitored during treatment, and abnormalities should be managed promptly.

2. Caution Is Needed in Patients with Renal Impairment

Mild to moderate renal impairment has no clinically meaningful effect on pharmacokinetics. The effects of severe renal impairment (creatinine clearance below 30 mL/min) and dialysis are not clear, so treatment should weigh benefits and risks and be closely monitored.

3. Pay Attention to CYP2C9 and CYP3A4 Interactions

Avatrombopag is mainly metabolized by CYP2C9 and CYP3A4. Concomitant use with moderate or strong dual inhibitors increases exposure and requires a lower starting dose; concomitant use with moderate or strong dual inducers decreases exposure and requires a higher starting dose. Platelet counts should be monitored and the dose adjusted during concomitant use.

4. Other Drugs and Herbal Products Should Be Reported to the Doctor

Patients should inform their doctor of all prescription drugs, over-the-counter medicines, vitamins, and herbal supplements. Some drugs may affect the efficacy of avatrombopag or increase toxicity, and medication adjustments should be made under medical guidance.