Drug Interactions between Creon and doxylamine / pseudoephedrine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

MONITOR: Exogenous pancreatic enzymes may interfere with the gastrointestinal absorption of folic acid and iron. The exact mechanism of interaction is unknown. In one study, investigators compared oral iron absorption over a 3-hour period in the presence and absence of exogenous pancreatic enzymes in 13 stable young adults with cystic fibrosis and 9 age-matched controls. There was no difference between patients and controls in iron absorption in the absence of exogenous pancreatic enzymes. However, significant impairment of iron absorption was observed in both groups after administration of pancrelipase one hour prior to iron administration. In the patient group, one hour after iron administration, there was a 188% increase in serum iron level above baseline in the absence of pancrelipase but only a 62% increase in the presence of pancrelipase. In the controls, percentage increases as well as peak serum iron levels were significantly higher in the absence of pancrelipase during all 3 hours after iron administration. Clinically, at least one-third of cystic fibrosis patients reportedly have iron deficiency. In the study, mean serum iron concentration was significantly lower in patients than in controls (11.9 versus 18.9 micromoles/L), and 5 of the patients but none of the controls had a serum iron concentration lower than 9 micromoles/L at baseline, presumably due to long-term treatment with pancreatic enzyme supplements.

MANAGEMENT: Patients receiving therapeutic iron or folate therapy should be monitored for potentially reduced hematologic response if pancreatic enzymes are administered concomitantly. Separating the times of administration may be helpful.

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.