In the population overall, the greatest likelihood of experiencing the first episode of any of these three TEAEs was greatest in the first week of treatment and decreased thereafter.According to Medscape, the most common (>10%) were: Nausea , Diarrhea (7-12%), Headache (2-11%). Less common side effects (1-10%) included: Abdominal pain (4-8%), Abdominal distension (3-6%), Flatulence (4-6%), Vomiting (3%), Loose stools (3%), Edema (1-3%), Abdominal discomfort (1-3%), Dizziness (3%), Chest discomfort/pain (2%), Dyspnea (2%), Dyspepsia (2%), Fatigue (2%), Dry mouth (1%). Contraindications
Known or suspected mechanical GI obstruction. Known hypersensitivity to lubiprostone or any ingredient in the formulation.There is no current data on use in people with liver or kidney complications. The effects on pregnancy have not been studied in humans but testing in guinea pigs resulted in fetal loss. Amitiza is not approved for use in children. Lubiprostone is contraindicated in patients exhibiting chronic diarrhea, bowel obstruction, or diarrhea-predominant irritable bowel syndrome. Mechanism of action
Lubiprostone is a bicyclic fatty acid derived from prostaglandin E1 that acts by specifically activating ClC-2 chloride channels on the apical aspect of gastrointestinal epithelial cells, producing a chloride-rich fluid secretion. These secretions soften the stool, increase motility, and promote spontaneous bowel movements (SBM). Symptoms of constipation such as pain and bloating are usually improved within one week, and SBM may occur within one day. Pharmacokinetics
Unlike many laxative products, lubiprostone does not show signs of drug tolerance, chemical dependency, or altered serum electrolyte concentration.
Superior vena cava syndrome (SVCS), is a group of symptoms caused by obstruction of the superior vena cava ("SVC"), a short, wide vessel carrying circulating blood into the heart. The majority of cases are caused by malignant tumors within the mediastinum, most commonly lung cancer and non-Hodgkins lymphoma, directly compressing or invading the SVC wall. Non-malignant causes are increasing in prevalence due to expanding use of intravascular devices (such as permanent central venous catheters and leads for pacemakers and defibrillators), which can result in thrombosis. Other non-malignant causes include benign mediastinal tumors, aortic aneurysm, infections, and fibrosing mediastinitis.Characteristic features are edema (swelling due to excess fluid) of the face and arms and development of swollen collateral veins on the front of the chest wall. Shortness of breath and coughing are quite common symptoms; difficulty swallowing is reported  in 11% of cases, headache in 6% and stridor (a high-pitched wheeze) in 4%. The symptoms are rarely life-threatening, though edema of the epiglottis can make breathing difficult, edema of the brain can cause reduced alertness, and in less than 5% of cases of SVCO, severe neurological symptoms or airway compromise are reported. Resolution of superior vena cava syndrome is directly related to the treatment of the underlying compression.