Hyperamylasemia in response to ritodrine or ephedrine administered to pregnant women.
BACKGROUND
Ritodrine and ephedrine can induce hyperamylasemia in pregnant women. The incidence of these beta-agonist-induced hyperamylasemias and their interaction on serum amylase activity are not known.


METHODS
Serum amylase activity was determined 12 to 24 hours after the administration of ritodrine alone (n = 140), ephedrine alone (n = 160), ephedrine and ritodrine simultaneously (n = 34), and ephedrine after prolonged (> or = 7 days) use of ritodrine (n = 101).


RESULTS
A significantly higher incidence of hyperamylasemia (amylase > 215 IU/L) was seen in a group treated with ritodrine alone (60/140, 43 percent), ephedrine alone (54/160, 34 percent), or ephedrine plus ritodrine (24/34, 71 percent) compared with untreated pregnant women (21/426, 4.9 percent). There was no difference in the incidence of hyperamylasemia among the untreated pregnant women and women who received ephedrine after long-term ritodrine (8/101, 7.9 percent). Isozyme patterns, examined in 72 out of the 146 women with hyperamylasemia after such medications, indicated that salivary-type amylase exclusively was hypersecreted.


CONCLUSIONS
Clinical doses of beta-agonists such as ephedrine or ritodrine induce hypersecretion of salivary-type amylase in approximately one-third of women who are pregnant. Desensitization to beta-agonists may occur after prolonged use of ritodrine.
Takahashi
T
T
Department of Obstetrics and Gynecology, Jichi Medical School, Tochigi, Japan.
Minakami
H
H
Tamada
T
T
Sato
I
I
D000293:Adolescent; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage* / Q000009:adverse effects; D000328:Adult; D000681:Amylases / Q000097:blood / Q000187:drug effects*; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D004809:Ephedrine / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D015994:Incidence; D007262:Infusions, Intravenous; D007752:Obstetric Labor, Premature / Q000201:enzymology / Q000517:prevention & control*; D011247:Pregnancy; D011446:Prospective Studies; D012189:Retrospective Studies; D012312:Ritodrine / Q000008:administration & dosage* / Q000009:adverse effects; D013997:Time Factors; D015149:Tocolytic Agents / Q000008:administration & dosage* / Q000009:adverse effects
D000318:Adrenergic beta-Agonists; D015149:Tocolytic Agents; D000681:Amylases; D004809:Ephedrine; D012312:Ritodrine