Morphine-Induced Nausea and Vomiting

Morphine-Induced Nausea and Vomiting

65. J.J., a 48-year-old woman, has advanced inoperable cervical cancer. The physician has ordered 30 mg of oral morphine solution every 4 hours for pain, but she has vomited after each dose despite apparently adequate doses of prochlorperazine. What can be done to relieve pain in J.J. who vomits after oral morphine?

Morphine and its derivatives induce nausea and vomiting by stimulating the chemoreceptor trigger zone (CTZ). Although the CTZ is stimulated initially, subsequent doses of morphine generally suppress the vomiting center. Because the incidence of nausea (40%) and vomiting (15%) increases in ambulatory patients, a vestibular component also is likely to be involved. If the vomiting is vestibular in origin, instructing J.J. to lie quietly, with as little head motion as possible for an hour or two, often will help. The nausea usually persists for 48 to 72 hours.²²⁰

Levorphanol (Levo-Dromoran) may cause less nausea and vomiting than other potent opioid analgesics at equianalgesic doses and might be an alternative to morphine if the aforementioned recommendations are ineffective in modifying J.J.'s nausea and vomiting. An equipotent dose of levorphanol for J.J., according to Table 8-3, would be 4 mg. The reported duration of action of levorphanol is 6 hours, longer than that of morphine.²²¹

Adjunctive drugs such as droperidol, prochlorperazine, hydroxyzine, scopolamine, and diphenhydramine have been used successfully to control opioid-induced nausea and vomiting. Patients who are extremely sensitive to this opioid-induced effect have to be placed on concurrent or scheduled antiemetics; transdermal scopolamine can be used for this purpose. Although much more costly, agents such as ondansetron may also be useful in patients who have contraindications to the use of phenothiazines or butyrophenones.

Posted in: General Care,Pain and Its Management