Close monitoring of potassium levels is required in patients receiving treatment with ACE inhibitors who are at risk of hyperkalemia. Another possible adverse effect specific for ACE inhibitors, but not for other RAAS blockers, is an increase in bradykinin level. A persistent dry cough is a relatively common adverse effect believed to be associated with the increases in bradykinin levels produced by ACE inhibitors, although the role of bradykinin in producing these symptoms has been disputed. Many cases of cough in people on ACE inhibitors may not be from the medication itself, however. People who experience this cough are often switched to angiotensin II receptor antagonists. Some (0.7%) develop angioedema due to increased bradykinin levels. A genetic predisposition may exist. A severe rare allergic reaction can affect the bowel wall and secondarily cause abdominal pain. Blood Hematologic effects, such as neutropenia, agranulocytosis and other blood dyscrasias, have occurred during therapy with ACE inhibitors, especially in people with additional risk factors. Pregnancy In pregnant women, ACE inhibitors taken during all the trimesters have been reported to cause congenital malformations, stillbirths, and neonatal deaths. Commonly reported fetal abnormalities include hypotension, renal dysplasia, anuria/oliguria, oligohydramnios, intrauterine growth retardation, pulmonary hypoplasia, patent ductus arteriosus, and incomplete ossification of the skull. Overall, about half of newborns exposed to ACE inhibitors are adversely affected, leading to birth defects. ACE inhibitors are ADEC pregnancy category D and should be avoided in women who are likely to become pregnant. In the U.S., ACE inhibitors must be labeled with a boxed warning concerning the risk of birth defects when taken during the second and third trimester. Their use in the first trimester is also associated with a risk of major congenital malformations, particularly affecting the cardiovascular and central nervous systems. Overdose Symptoms and Treatment: There are few reports of ACE inhibitor overdose in the literature. The most likely manifestations are hypotension, which may be severe, hyperkalemia, hyponatremia and renal impairment with metabolic acidosis. Treatment should be mainly symptomatic and supportive, with volume expansion using normal saline to correct hypotension and improve renal function, and gastric lavage followed by activated charcoal and a cathartic to prevent further absorption of the drug. Captopril, enalapril, lisinopril and perindopril are known to be removable by hemodialysis. Contraindications and precautions The ACE inhibitors are contraindicated in people with: Pregnancy or breastfeeding Previous angioedema associated with ACE inhibitor therapy Bilateral renal artery stenosis Hypersensitivity to