Following oral administration of a single dose of 5 or 10 mg, ulipristal acetate is rapidly absorbed, with a C max of ± ng/ml and ± ng/ml occurring approximately 1 h after ingestion, and with an AUC 0-∞ of ± /ml and ± /ml, respectively. Ulipristal acetate is rapidly transformed into a pharmacologically active metabolite with a C max of ± ng/ml and ± ng/ml also occurring approximately 1 h after ingestion, and with an AUC 0-∞ of ± /ml and ± /ml respectively.
Other Drug Interactions The anti-tuberculosis drug rifampin has been found to produce a marked (50%) reduction in serum methadone levels, leading to the appearance of symptoms of withdrawal in well-stabilized methadone maintenance patients. Similar effects on serum methadone levels have been observed for carbamazepine, phenobarbital, and phenytoin. The presumed mechanism for this effect is the induction of methadone metabolizing enzymes . Since ORLAAM (levomethadyl acetate) is metabolized into a more active metabolite, nor-LAAM, administration of these drugs may increase ORLAAM (levomethadyl acetate) 's peak activity and/or shorten its duration of action.
Importance of discussing with patient and/or guardian the risk of potential water intoxication and/or hyponatremia, fluid restriction (particularly in pediatric and geriatric patients), and monitoring of fluid intake (particularly during acute intercurrent illness [., systemic infections, fever, recurrent vomiting or diarrhea] and under conditions associated with increased water intake [., extremely hot weather, vigorous exercise]). 101 112 115 116 117 Importance of promptly informing clinicians if the patient’s fluid intake changes or if symptoms of hyponatremia (., nausea, vomiting, fatigue, muscle cramps or weakness) occur. 115