Tracheomalacia is a condition or incident where the cartilage that keeps the airway (trachea) open is soft such that the trachea partly collapses especially during increased airflow. This condition is most commonly seen in infants and young children. The usual symptom is stridor when a person breathes out. This is usually known as a collapsed windpipe. The trachea normally opens slightly during breathing in and narrows slightly during breathing out. These processes are exaggerated in tracheomalacia, leading to airway collapse on breathing out. If the condition extends further to the large airways (bronchi) (if there is also bronchomalacia), it is termed tracheobronchomalacia. The same condition can also affect the larynx, which is called laryngomalacia. The term is from trachea and the Greek μαλακία, softening

Signs and symptoms
Tracheomalacia occurs when the walls of the trachea collapse. This can happen because the walls of the windpipe are weak, or it can happen because something is pressing on it. This may include hypotonia of the trachealis muscle. The whole windpipe can be affected, or only a short piece of it. If the collapsed part of the windpipe goes past the area where the windpipe branches off into the two lungs, it is called bronchomalacia.This problem causes noisy or difficult breathing in the first 1 to 2 months after birth. This is called congenital tracheomalacia (it was present at birth). It is not very common. Babies born with tracheomalacia may have other health issues like a heart defect, reflux or developmental delay.
: 334  It has been associated with acute liver damage.In 2008 the US label was updated with a warning concerning a risk of premature closure of the ductus arteriosus in pregnancy.In October 2020, the U.S. Food and Drug Administration (FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They recommend avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy. Overdose
Symptoms of overdosing include kidney failure, gastrointestinal problems, bleeding, rashes, confusion, hallucinations, vertigo, seizures, and loss of consciousness. It is treated with induction of vomiting, gastric lavage, bone char, and control of electrolytes and vital functions. Interactions
Interactions are broadly similar to those of other NSAIDs. Mefenamic acid interferes with the anti–blood clotting mechanism of Aspirin. It increases the blood thinning effects of warfarin and phenprocoumon because it displaces them from their plasma protein binding and increases their free concentrations in the bloodstream. It adds to the risk of gastrointestinal ulcera associated with corticosteroids and selective serotonin reuptake inhibitors. It can increase the risk for adverse effects of methotrexate and lithium by lowering their excretion via the kidneys. It can increase the kidney toxicity of ciclosporin and tacrolimus. Combination with antihypertensive drugs such as ACE inhibitors, sartans and diuretics can decrease their effectiveness as well as increase the risk for kidney toxicity.