Drug Interactions between Meprozine and sodium polystyrene sulfonate

MONITOR: Coadministration with medications that can cause constipation such as opioids may increase the risk of intestinal injuries associated with the use of sodium polystyrene sulfonate. Cases of intestinal necrosis, which may be fatal, and other serious gastrointestinal adverse events including bleeding, ischemic colitis, and perforation have been reported during treatment with sodium polystyrene sulfonate. Most cases occurred during concomitant use of sorbitol, and risk factors were present in many of the patients including prematurity, history of intestinal disease or surgery, hypovolemia, and renal insufficiency or failure. Data are limited in the medical literature regarding concomitant use of sodium polystyrene sulfonate and opioids. In one case report, intestinal obstruction occurred in an 86-year-old man who received sodium polystyrene sulfonate 15 g orally once daily for 4 days while also being treated with aluminum hydroxide 5 mL four times daily and slow-release morphine 10 mg three times daily. Although the interaction is primarily attributed to concretions of aluminum hydroxide in the intestine, the potential contribution of morphine is unknown.

MANAGEMENT: Because opioids commonly cause constipation, caution is advised when used during treatment with sodium polystyrene sulfonate. The prescribing information recommends avoiding the use of sodium polystyrene sulfonate in patients who are at risk for developing constipation or impaction, including those with a history of impaction, chronic constipation, inflammatory bowel disease, ischemic colitis, vascular intestinal atherosclerosis, previous bowel resection, or bowel obstruction, as well as those who have not had a bowel movement post-surgery. If clinically significant constipation develops, treatment with sodium polystyrene sulfonate should be discontinued until normal bowel motion is resumed. Concomitant administration of sorbitol is not recommended.

ADJUST DOSE: The central nervous system and respiratory depressant effects of meperidine may be potentiated by concomitant use of other agents with CNS depressant effects. An increased risk of serious adverse reactions such as respiratory depression, hypotension, profound sedation, syncope, coma, and even death should be considered, particularly in elderly or debilitated patients.

MANAGEMENT: Caution and dosage adjustments are advisable when meperidine is used in combination with other narcotic analgesics, general anesthetics, phenothiazines, sedative-hypnotics, tranquilizers, tricyclic antidepressants, or other CNS depressants such as alcohol. A lower dosage of meperidine should be considered initially, then titrated carefully according to pain level and clinical response. Meperidine dosage reductions of 25% to 50% have been recommended for patients receiving phenothiazines and other tranquilizers. Patients should be advised to avoid rising abruptly from a sitting or recumbent position, and to notify their physician if they experience dizziness, lightheadedness, orthostasis, syncope, tachycardia, or excessive CNS effects that interfere with their normal activities. Patients should also avoid driving or operating hazardous machinery until they know how these medications affect them.