Cimetidine accelerates the rate of duodenal ulcer healing. Healing rates reported in U.S. and foreign controlled trials with cimetidine are summarized below, beginning with the regimen providing the lowest nocturnal dose.
Table 3. Duodenal Ulcer Healing Rates with Various Dosage Regimens of Cimetidine
Averages from controlled clinical trials.
Regimen | 300 mg 4 times daily | 400 mg twice daily | 800 mg at bedtime | 1,600 mg at bedtime |
Week 4 | 68% | 73% | 80% | 86% |
Week 6 | 80% | 80% | 89% | - |
Week 8 | - | 92% | 94% | - |
A U.S., double-blind, placebo-controlled, dose-ranging study demonstrated that all once-daily at bedtime regimens of cimetidine was superior to placebo in ulcer healing and that 800 mg of cimetidine at bedtime healed 75% of patients at 4 weeks. The healing rate with 800 mg at bedtime was significantly superior to 400 mg at bedtime (66%) and not significantly different from 1,600 mg at bedtime (81%).
In the U.S. dose-ranging trial, over 80% of patients receiving 800 mg of cimetidine at bedtime experienced nocturnal pain relief after one day. Relief from daytime pain was reported in approximately 70% of patients after 2 days. As with ulcer healing, the 800 mg dose at bedtime was superior to 400 mg at bedtime and not different from 1,600 mg at bedtime.
In foreign, double-blind studies with 800 mg of cimetidine at bedtime, 79% to 85% of patients were healed at 4 weeks.
While short-term treatment with cimetidine can result in complete healing of the duodenal ulcer, acute therapy will not prevent ulcer recurrence after cimetidine has been discontinued. Some follow-up studies have reported that the rate of recurrence once therapy was discontinued was slightly higher for patients healed on cimetidine than for patients healed on other forms of therapy; however, the patients treated with cimetidine generally had more severe disease.
Clinical studies have indicated that suppression of nocturnal acid is the most important factor in duodenal ulcer healing (see
CLINICAL PHARMACOLOGY: Antisecretory Activity: Acid Secretion). This is supported by recent clinical trials (see
CLINICAL TRIALS: Duodenal Ulcer: Active Duodenal Ulcer). Therefore, there is no apparent rationale, except for familiarity with use, for treating with anything other than a once-daily at bedtime dosage regimen.
In a U.S. dose-ranging study of 400 mg at bedtime, 800 mg at bedtime and 1,600 mg at bedtime, a continuous dose-response relationship for ulcer healing was demonstrated.
However, 800 mg at bedtime is the dose of choice for most patients, as it provides a high healing rate (the difference between 800 mg at bedtime and 1,600 mg at bedtime being small), maximal pain relief, a decreased potential for drug interactions (see
PRECAUTIONS: Drug Interactions) and maximal patient convenience. Patients unhealed at 4 weeks, or those with persistent symptoms, have been shown to benefit from 2 weeks to 4 weeks of continued therapy.
It has been shown that patients who both have an endoscopically demonstrated ulcer larger than 1 cm and are also heavy smokers (i.e., smoke 1 pack of cigarettes or more per day) are more difficult to heal. There is some evidence which suggests that more rapid healing can be achieved in this subpopulation with 1,600 mg of cimetidine tablets at bedtime. While early pain relief with either 800 mg at bedtime or 1,600 mg at bedtime is equivalent in all patients, 1,600 mg at bedtime provides an appropriate alternative when it is important to ensure healing within 4 weeks for this subpopulation. Alternatively, approximately 94% of all patients will also heal in 8 weeks with 800 mg of cimetidine tablets at bedtime.
Other regimens of cimetidine tablets in the United States which have been shown to be effective are: 300 mg 4 times daily, with meals and at bedtime, the original regimen with which U.S. physicians have the most experience, and 400 mg twice daily, in the morning and at bedtime (see
CLINICAL TRIALS: Duodenal Ulcer: Active Duodenal Ulcer).
Concomitant antacids should be given as needed for relief of pain. However, simultaneous administration of cimetidine tablets and antacids is not recommended, since antacids have been reported to interfere with the absorption of cimetidine.
While healing with cimetidine tablets often occurs during the first week or two, treatment should be continued for 4 weeks to 6 weeks unless healing has been demonstrated by endoscopic examination.