Linaclotide (lin´´ a kloe´ tide; Linzess – Ironwood/Forest), a guanylate cyclase-C receptor agonist, was recently approved by the FDA for oral treatment of chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C) in adults. It is the second drug approved for this indication; lubiprostone (Amitiza), a metabolite of prostaglandin E1, was the first.

The guanylate cyclase-C receptor agonist linaclotide (Linzess – Abbvie/Ironwood) was first approved by the FDA in 2012 for treatment of chronic idiopathic constipation and irritable bowel syndrome with constipation in adults. The drug has now been approved for treatment of functional constipation in patients 6-17 years old. Linaclotide is the only drug to be approved in the US for treatment of functional constipation.

The FDA has approved lubiprostone (Amitiza - Sucampo/Takeda), a chloride channel activator, for treatment of chronic idiopathic constipation in adults. The only other prescription drug approved by the FDA for this indication (in 2004 for adults <= 65 years old) is tegaserod (Zelnorm), a partial agonist of serotonin that is also approved for constipation-predominant irritable bowel syndrome in women. Of course, numerous over-the-counter products are available for treatment of constipation.

The FDA has approved use of lubiprostone (Amitiza) for treatment of opioid-induced constipation in adults with chronic non-cancer pain. The drug was previously approved for chronic idiopathic constipation and irritable bowel syndrome with constipation.

The FDA has approved naloxegol (Movantik – AstraZeneca), a pegylated derivative of the opioid antagonist naloxone, for oral treatment of opioid-induced constipation in adults with chronic noncancer pain. It is the only oral opioid antagonist approved for this indication in the US.

The FDA has approved the 5-HT4 receptor agonist prucalopride (Motegrity – Shire) for treatment of chronic idiopathic constipation (CIC) in adults. Prucalopride is the only drug currently approved in the US for treatment of CIC that stimulates colonic peristalsis. It has been available in Europe and Canada for several years.

The FDA has approved plecanatide (Trulance – Synergy), a guanylate cyclase-C receptor agonist, for treatment of chronic idiopathic constipation (CIC) in adults. Linaclotide (Linzess), another guanylate cyclase-C receptor agonist, and lubiprostone (Amitiza), a chloride channel activator, were approved earlier for treatment of CIC in adults.

The FDA has approved subcutaneous injection of methylnaltrexone (Relistor - Wyeth/Progenics), a selective mu-opioid receptor antagonist, for treatment of opioid-induced constipation in patients with advanced illness (such as incurable cancer or end-stage chronic obstructive pulmonary disease) who are receiving palliative care.

The FDA has approved the opioid receptor antagonist naldemedine (Symproic – Shionogi) for treatment of opioid-induced constipation (OIC) in adults with chronic noncancer pain. Naldemedine is the third oral peripherally-acting mu-opioid receptor antagonist (PAMORA) to be approved for this indication; naloxegol (Movantik) and methylnaltrexone (Relistor) were approved earlier.

Tegaserod maleate (teg a ser' od; Zelnorm - Novartis), a serotonin derivative, has received FDA approval for short-term treatment of women with irritable bowel syndrome (IBS) whose primary symptom is constipation. Alosetron (Lotronex), which was withdrawn previously because of toxicity, will soon be available again for women with severe diarrhea-predominant IBS (Medical Letter 2002; 44:67).