Pacritinib is used in adult patients with myelofibrosis and a platelet count below 50×10⁹/L. For use in special populations, attention should focus on hepatic function, renal function, pregnancy, lactation, and fertility.

I. Patients with Hepatic or Renal Impairment

1. Severe Hepatic Impairment

The recommended dosage is 100 mg twice daily.

If treatment is not effective after 12 weeks and there are no safety concerns, the dosage may be increased to 200 mg twice daily.

Safety should be monitored continuously during treatment.

No dosage adjustment is needed for mild or moderate hepatic impairment.

2. Renal Impairment

Avoid use in patients with eGFR below 30 mL/min.

Drug exposure is increased in this population, raising the risk of adverse reactions.

No dosage adjustment is needed for mild or moderate renal impairment.

II. Pregnancy, Lactation, and Fertility-Related Populations

1. Pregnancy

There are no data on use in pregnant women, and the drug-associated risk cannot be assessed.

Animal studies show maternal toxicity and embryo loss at exposures below the recommended human dose.

Pregnant women should be informed of the potential risk to the fetus, and use should be based on weighing maternal and fetal benefits and risks.

2. Lactation

It is not known whether pacritinib is excreted in human milk.

Because of the potential for serious adverse reactions in a breastfed child, breastfeeding is not recommended during treatment and for 2 weeks after the last dose.

3. Effects on Fertility

Animal studies show that pacritinib can reduce mating and fertility indices in male mice.

It may impair male fertility in humans, and those with reproductive needs should consult a physician in advance.

III. Pediatric and Geriatric Patients

1. Pediatric Patients

Safety and effectiveness have not been established, and use is not recommended.

2. Geriatric Patients

Clinical studies did not include a sufficient number of patients aged 65 years and older.

It is not yet known whether geriatric patients respond differently from younger patients.

Use should be based on an assessment of overall condition, with enhanced monitoring.

IV. Other Populations Requiring Attention

1. Patients at Risk of Bleeding

Avoid use in patients with active bleeding.

Discontinue the drug 7 days before planned surgery or invasive procedures, and resume only after hemostasis is confirmed.

2. Patients with Cardiovascular Risk

Risk may be increased in current or past smokers and those with other cardiovascular risk factors.

Benefits and risks should be assessed before use, and related symptoms should be managed promptly.

3. Patients with Infection

Starting treatment should be delayed until active serious infection is controlled.

Signs of infection should be observed and managed promptly during treatment.

4. Patients Receiving Concomitant Medications

Concomitant use with strong CYP3A4 inhibitors or inducers is prohibited.

When used with moderate CYP3A4 inhibitors, adverse reactions should be monitored.

When used with P-gp, BCRP, or CYP1A2 substrates, monitoring is needed and substrate doses should be adjusted.

The drug may reduce the effectiveness of hormonal contraceptives; alternative or additional contraceptive measures should be used during treatment and for 30 days after the last dose.