Intravenous histamine H2-receptor antagonists and parenteral nutrition: patterns of use.

Patterns of use of i.v. histamine h2-receptor antagonists (H2RAs) and parenteral nutrient solutions in patients receiving both given separately or as admixtures were studied. Consecutive adult patients at a university teaching hospital were placed in an "admixed group," consisting of all those who received an i.v. H2RA as a parenteral nutrient solution additive, or a "nonadmixed group," consisting of all those who received an i.v. H2RA and a parenteral nutrient solution as separate infusions. Data were collected for many variables, including interruptions in therapy, route and method of administration, indication for use, total daily dose of H2RA, patient demographic data, and any additional anti-ulcer drugs prescribed. A total of 128 patients received 158 regimens of therapy, 60 regimens in the admixed group and 98 in the nonadmixed group. There was at least one interruption in i.v. H2RA therapy for 32% of the admixed-group regimens and 33% of the nonadmixed-group regimens. When an interruption occurred, patients in the admixed group missed an average of 40% of their daily H2RA dose, compared with 53% for the nonadmixed group. No alternative anti-ulcer drug was given on 10 (23%) of the 42 days when intensive care patients had an interruption in H2RA therapy, versus 33 (55%) of the 60 days of H2RA interruption for non-intensive-care patients. Interruptions in i.v. H2RA therapy occurred more frequently when the H2RA was a component of the nutrient solution than when it was given as a separate infusion. Supplemental anti-ulcer therapy was typically not provided during interruptions in H2RA therapy, regardless of the method of administration.