Cocaine can cause serious abdominal problems as well as chest pain and breathing difficulties, a leading surgeon said on Friday.

“Abdominal complications from cocaine abuse are life-threatening and require emergency surgery,” said Luke Meleagros, of North Middlesex University Hospital, in Britain’s Journal of the Royal Society of Medicine.

With an estimated 344,000 people using cocaine and 17,000 taking crack cocaine each month in Britain, Meleagros and his colleagues fear health problems in drug users will increase, particularly in London where drug abuse is more common.

“As the number of cocaine abusers rises, we expect the accompanying health problems to spread across the country,” Meleagros said in a statement.

Cocaine is an addictive stimulant drug. Crack is a form of cocaine that comes in a rock crystal. The name derives from the crackling sound it produces when heated.

The drug can increase heart rate and blood pressure, as well as constrict blood vessels. Many cocaine-related deaths result from cardiac arrest or seizure.

“Abdominal complications are more common with users of crack cocaine and in poor, inner city areas,” said Meleagros.

“However, we suspect that there is an under-reporting or misrecognition of the problem in other areas, particularly affluent areas, as these complications occur in cocaine users as well.”

Symptoms of abdominal problems, which can occur within an hour of taking the drug, include pain, tenderness, nausea, vomiting and bloody diarrhea.