February 15, 2007

Low-Dose Morphine Calms Chronic Cough

THURSDAY, Feb. 15 (HealthDay News) -- Low-dose, slow-release morphine can give chronic coughers substantial relief, according to a new British study.

"Ours is the first study which proves morphine can be effective in chronic cough," said study author Dr. Alyn H. Morice, a professor of respiratory medicine at the University of Hull, in East Yorkshire.

"We are also able to quantify its effect for the first time," he said. "Two-thirds of patients will respond to the low dose we use."

Larger doses of the drug are used to manage chronic pain, Morice said. "Injecting high doses is what is bad for you and leads to addiction," he added.

The study findings are published in the February issue of the American Journal of Respiratory and Critical Care Medicine.

In the study, Morice and his colleagues evaluated 27 adults -- 18 women and nine men -- who were being treated at a hospital cough clinic. All had a persistent cough for more than three months; the average age was 55.

Conditions such as lung disease were ruled out. Then the researchers gave the patients either 5 milligrams of slow-release morphine or a placebo twice daily for four weeks; the participants didn't know which therapy they were taking.

The coughers returned to the clinic three times and rated their cough using a commonly used questionnaire that assigns a score based on physical, social and psychological effects of the cough. They were told not to use any other cough products during the study.

Benefits occurred by the fifth day of treatment and continued throughout the four-week study. The daily "cough score" levels dropped by 40 percent.

Then, 18 of the 27 people decided to continue in a three-month extension of the study, with most increasing their morphine dose to 10 milligrams twice a day.

At the study's end, similar improvements in cough were noted at both doses, Morice found.

"Mankind has been using morphine for thousands of years," he said. "It is very safe. Constipation is the only side effect which we encounter with any frequency."

Forty percent of those taking the morphine reported constipation; 25 percent complained of drowsiness.

Chronic cough is not just a nuisance, said Dr. Chester Griffiths, an ear-nose-throat specialist and vice chief of staff at Santa Monica-UCLA Medical Center and Orthopaedic Hospital, in Santa Monica, Calif.

Chronic cough, defined as one that lasts more than three to six months, can cause complications such as cracked ribs or a herniated disc, he said.

Griffiths emphasized it's important to first rule out other underlying reasons for a chronic cough, such as allergies or asthma. "When you have ruled out everything else, you have to suppress it because the cough can cause complications," he said.

And the morphine in the study did suppress the cough, he said.

More information

To learn more about chronic cough, visit the American Academy of Family Physicians.

SOURCES: Alyn H. Morice, M.D., professor, respiratory medicine, University of Hull, East Yorkshire, Great Britain; Chester Griffiths, M.D., assistant clinical professor and vice chief of staff, Santa Monica-UCLA Medical Center and Orthopaedic Hospital, Santa Monica, Calif.; February 2007 American Journal of Respiratory and Critical Care Medicine
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