Tradipitant

◉ Summary of Use during Lactation；No information is available on the use of tradipitant during breastfeeding. Because tradipitant is more than 96% bound to plasma proteins, the amount in milk is likely to be low. If the mother requires tradipitant, it is not a reason to discontinue breastfeeding. Monitor the infant for sedation.；◉ Effects in Breastfed Infants；Relevant published information was not found as of the revision date.；◉ Effects on Lactation and Breastmilk；Relevant published information was not found as of the revision date.

Tradipitant inhibits the NK-1 receptor with a Ki of 0.062 nM and effectively blocks Substance P-induced intracellular calcium mobilization. The drug crosses the blood-brain barrier and achieves high receptor occupancy; a clinical study demonstrated that tradipitant occupies approximately 93% of NK-1 receptors in the frontal cortex following multiple doses. In clinical trials involving preventing vomiting induced by motion, single oral doses of 85 mg and 170 mg demonstrated significant efficacy in reducing vomiting incidence compared to placebo, with effects observed in variable sea conditions. At the maximum recommended single dose of 170 mg, tradipitant does not cause clinically significant prolongation of the QTc interval.

Tradipitant is a selective, high-affinity antagonist of the human substance P/neurokinin-1 (NK-1) receptor. NK-1 receptors are widely distributed in the central nervous system, particularly in brainstem nuclei such as the nucleus tractus solitarius (NTS) and the area postrema, which play a critical role in the regulation of vomiting, as well as in the peripheral gastrointestinal tract. Tradipitant works by blocking the binding of Substance P, the endogenous ligand, to NK-1 receptors, thereby inhibiting the transmission of emetogenic sensory signals from vestibular and visceral sources to the vomiting center. Unlike some other anti-emetics, tradipitant does not exhibit affinity for serotonin (5-HT3), dopamine (D2), cholinergic, or histamine (H1) receptors.

Tradipitant is extensively metabolized; however, the metabolic pathways have not been fully characterized. In vitro findings suggest that non-CYP450-mediated processes and CYP enzymes (CYP3A4, CYP2C19, and to a lesser extent by CYP2C8) are involved in the metabolism of tradipitant. Tradipitant is also glucuronidated by UGT1A4 and UGT2B7. Four major metabolites (M2, M3, M4, and M8) were identified in plasma. Following a single dose of 85 mg tradipitant in healthy subjects under fasting conditions, the AUCs of M2, M3, M4, and M8 represent 40%, 33%, 43%, and 42% of the parent AUC, respectively. The major metabolites of tradipitant (M2, M3, M4, and M8) exhibited NK-1 receptor binding affinities comparable to those of the parent drug.

Absolute oral bioavailability has not been studied in humans. Following a single dose of 85 mg tradipitant in healthy subjects under fasting conditions, tradipitant geometric mean Cmax was 84.7 ng/mL, AUC0-inf was 1839 ng x h/mL, and the median Tmax was 2.0 hours. Following a single dose of 170 mg tradipitant in healthy subjects under fasting conditions, tradipitant geometric mean Cmax was 112 ng/mL, AUC0-inf was 3,526 ng x h/mL, and the median Tmax was 1.50 hours. In healthy subjects, a high-fat meal increased AUC0-inf and Cmax, while delaying Tmax.

Following a single oral dose of radiolabeled tradipitant 25 mg, approximately 88% of the dose was recovered, with 80% of the dose in feces and 7% in urine. Unchanged tradipitant was minimal in feces and was not detected in urine.

The apparent volume of distribution (Vd/F) of tradipitant is 1956 L in healthy subjects.

The apparent oral clearance of tradipitant is 41.7 L/hour in healthy subjects.