Opioid as codeine, has similarly demonstrated little benefit in several recent studies.) Low dose morphine may help chronic cough but its use is limited by side effects. In cases of diarrhea-predominate irritable bowel syndrome, opioids may be used to suppress diarrhea. Loperamide is a peripherally selective opioid available without a prescription used to suppress diarrhea. The ability to suppress diarrhea also produces constipation when opioids are used beyond several weeks. Naloxegol, a peripherally-selective opioid antagonist is now available to treat opioid induced constipation. Opioids may help with shortness of breath particularly in advanced diseases such as cancer and COPD among others.
Loperamide no significant absorption from the gut and does not cross the blood–brain barrier when used at normal doses. It works by slowing the contractions of the intestines. Loperamide was first made in 1969 and used medically in 1976. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Loperamide is available as an inexpensive generic medication. The wholesale cost in the developing world is about US$0.004 to 0.040 per dose. In August 2016, the US retail cost is about US$0.31 per dose. Loperamide is effective for the treatment