The dual (ET and ET) endothelin receptor antagonist bosentan was approved in 2001. Sitaxentan (Thelin) was approved for use in Canada, Australia, and the European Union, but not in the United States. In 2010, Pfizer withdrew Thelin worldwide because of fatal liver complications. A similar drug, ambrisentan is marketed as Letairis in the U.S. by Gilead Sciences.

Treatments for primary pulmonary hypertension such as prostacyclins and endothelin receptor antagonists can be fatal in people with PVOD due to the development of severe pulmonary edema, and worsening symptoms after initiation of these medications may be a clue to the diagnosis of pulmonary veno occlusive disease.

The definitive therapy is lung transplantation, though transplant rejection is always a possibility, in this measures must be taken in terms of appropriate treatment and medication.

The U.S. FDA approved sildenafil, a selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5), for the treatment of PAH in 2005. It is marketed for PAH as Revatio. In 2009, they also approved tadalafil, another PDE5 inhibitor, marketed under the name Adcirca. PDE5 inhibitors are believed to increase pulmonary artery vasodilation, and inhibit vascular remodeling, thus lowering pulmonary arterial pressure and pulmonary vascular resistance.

Tadalafil is taken orally, as well as sildenafil, and it is rapidly absorbed (serum levels are detectable at 20 minutes). The T (biological half-life) hovers around 17.5 hours in healthy subjects. Moreover, if we consider pharmacoeconomic implications, patients that take tadalafil would pay two-thirds of the cost of sildenafil therapy. However, there are some adverse effects of this drug such as headache, diarrhea, nausea, back pain, dyspepsia, flushing and myalgia.

Pulmonary fibrosis creates scar tissue. The scarring is permanent once it has developed. Slowing the progression and prevention depends on the underlying cause:

- Treatment options for idiopathic pulmonary fibrosis are very limited. Though research trials are ongoing, there is no evidence that any medications can significantly help this condition. Lung transplantation is the only therapeutic option available in severe cases. Since some types of lung fibrosis can respond to corticosteroids (such as prednisone) and/or other medications that suppress the body's immune system, these types of drugs are sometimes prescribed in an attempt to slow the processes that lead to fibrosis.

- Two pharmacological agents intended to prevent scarring in mild idiopathic fibrosis are pirfenidone, which reduced reductions in the 1-year rate of decline in FVC. Pirfenidone also reduced the decline in distances on the 6-minute walk test, but had no effect on respiratory symptoms. The second agent is nintedanib, which acts as antifibrotic, mediated through the inhibition of a variety of tyrosine kinase receptors (including platelet-derived growth factor, fibroblast growth factor, and vascular endothelial growth factor). A randomized clinical trial showed it reduced lung-function decline and acute exacerbations.

- Anti-inflammatory agents have only limited success in reducing the fibrotic progress. Some of the other types of fibrosis, such as non-specific interstitial pneumonia, may respond to immunosuppressive therapy such as corticosteroids. However, only a minority of patients respond to corticosteroids alone, so additional immunosuppressants, such as cyclophosphamide, azathioprine, methotrexate, penicillamine, and cyclosporine may be used. Colchicine has also been used with limited success. There are ongoing trials with newer drugs such as IFN-γ and mycophenolate mofetil..

- Hypersensitivity pneumonitis, a less severe form of pulmonary fibrosis, is prevented from becoming aggravated by avoiding contact with the causative material.

- Oxygen supplementation improves the quality of life and exercise capacity. Lung transplantation may be considered for some patients.

Hypoxia caused by pulmonary fibrosis can lead to pulmonary hypertension, which, in turn, can lead to heart failure of the right ventricle. Hypoxia can be prevented with oxygen supplementation.

Pulmonary fibrosis may also result in an increased risk for pulmonary emboli, which can be prevented by anticoagulants.

Pulmonary venoocclusive disease is rare, difficult to diagnose, and probably frequently misdiagnosed as idiopathic pulmonary arterial hypertension. Prevalence in parts of Europe is estimated to be 0.1-0.2 cases per million.

PVOD appears to occur as frequently in men as in women, and age at diagnosis ranges from 7–74 years with a median of 39 years. PVOD may occur in patients with associated diseases such as HIV, bone marrow transplantation, and connective tissue diseases. PVOD has also been associated with several chemotherapy regimens such as bleomycin, BCNU, and mitomycin.

ILD is not a single disease, but encompasses many different pathological processes. Hence treatment is different for each disease.

If a specific occupational exposure cause is found, the person should avoid that environment. If a drug cause is suspected, that drug should be discontinued.

Many cases due to unknown or connective tissue-based causes are treated with corticosteroids, such as prednisolone. Some people respond to immunosuppressant treatment. Patients with a low level of oxygen in the blood may be given supplemental oxygen.

Pulmonary rehabilitation appears to be useful. Lung transplantation is an option if the ILD progresses despite therapy in appropriately selected patients with no other contraindications.

On October 16, 2014, the Food and Drug Administration approved a new drug for the treatment of Idiopathic Pulmonary Fibrosis (IPF). This drug, Ofev (nintedanib), is marketed by Boehringer Ingelheim Pharmaceuticals, Inc. This drug has been shown to slow the decline of lung function although the drug has not been shown to reduce mortality or improve lung function. The estimated cost of the drug per year is approximately $94,000.

Decision making for patients with CTEPH can be complex and needs to be managed by CTEPH teams in expert centres. CTEPH teams comprise cardiologists and pulmonologists with specialist PH training, radiologists, experienced PEA surgeons with a significant caseload of CTEPH patients per year and physicians with percutaneous interventional expertise. Currently, there are three recognised targeted treatment options available: pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA) and pulmonary vasodilator drug treatment for inoperable patients.

Specialist imaging using either magnetic resonance or invasive PA is necessary to determine risks and benefits of interventional treatment with PEA or BPA.

Infliximab, an immune-suppressing antibody, has been tested in COPD; there was a possibility of harm with no evidence of benefit.

Roflumilast, cilomilast, and phosphodiesterase 4 inhibitors act as a bronchodilator and as an anti-inflammatory. They show promise in decreasing the rate of exacerbations, but do not appear to change a persons quality of life. Roflumilast and cilomilast may be associated with side effects such as gastrointestinal issues and weight loss. Sleep disturbances and mood disturbances related to roflumilast have also been reported.

Several new long-acting agents are under development. Treatment with stem cells is under study. While there is tentative data that it is safe, and the animal data is promising, there is little human data as of 2017. The human data has shown poor results.

A procedure known as target lung denervation, which involves decreasing the parasympathetic nervous system supply of the lungs, is being studied but does not have sufficient data to determine its use. The effectiveness of alpha-1 antitrypsin augmentation treatment for people who have alpha-1 antitrypsin deficiency is unclear.

Research continues into the use of telehealthcare to treat people with COPD when they experience episodes of shortness of breath; treating people remotely may reduce the number of emergency-room visits and improve the person's quality of life.

Standard medical treatment consists of anticoagulants (blood thinners), diuretics, and oxygen. Lifelong anticoagulation is recommended, even after PEA. Routine inferior vena cava filter placement is not recommended.

In patients with non-operable CTEPH or persistent/recurrent PH after PEA, there is evidence for benefit from pulmonary vasodilator drug treatment. The microvascular disease component in CTEPH has provided the rationale for off-label use of drugs approved for PAH. Currently, only riociguat (a stimulator of soluble guanylate cyclase) is approved for treatment of adults with inoperable CTEPH or persistent or recurrent CTEPH after surgical treatment. Other drug trials are ongoing in patients with inoperable CTEPH, with macitentan recently proving efficacy and safety in MERIT

The exact cause of rheumatoid lung disease is unknown. However, associated factors could be due largely to smoking. Sometimes, the medicines used to treat rheumatoid arthritis, especially methotrexate, may result in lung disease.

Prevention's:

- Stop smoking: Chemicals found in cigarettes can irritate already delicate lung tissue, leading to further complications.

- Having regular checkups: The doctor could listen to lungs and monitor breathing, because lung problems that are detected early can be easier to treat.

Many people with this condition have no symptoms. Treatment is aimed at the health problems causing the lung problem and the complications caused by the disorder.

Fast-acting drugs for RA include aspirin and corticosteroids, which alleviate pain and reduce inflammation. Slow-acting drugs termed disease modifying antirheumatic drugs (DMARDs), include gold, methotrexate and hydroxychloroquine (Plaquenil), which promote disease remission and prevent progressive joint destruction. In patients with less severe RA, pain relievers, anti-inflammatory drugs and physical rest are sufficient to improve quality of life. In patients with joint deformity, surgery is the only alternative for recovering articular function.

Prognosis is related to the underlying disorder and the type and severity of lung disease. In severe cases, lung transplantation can be considered. This is more common in cases of bronchiolitis obliterans, pulmonary fibrosis, or pulmonary hypertension. Most complications are not fatal, but does reduce life expectancy to an estimated 5 to 10 years.

Supplemental oxygen is recommended in those with low oxygen levels at rest (a partial pressure of oxygen less than 50–55 mmHg or oxygen saturations of less than 88%). In this group of people, it decreases the risk of heart failure and death if used 15 hours per day and may improve people's ability to exercise. In those with normal or mildly low oxygen levels, oxygen supplementation may improve shortness of breath when given during exercise, but may not improve breathlessness during normal daily activities or affect the quality of life. A risk of fires and little benefit exist when those on oxygen continue to smoke. In this situation, some recommend against its use. During acute exacerbations, many require oxygen therapy; the use of high concentrations of oxygen without taking into account a person's oxygen saturations may lead to increased levels of carbon dioxide and worsened outcomes. In those at high risk of high carbon dioxide levels, oxygen saturations of 88–92% are recommended, while for those without this risk, recommended levels are 94–98%.

Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of lung diseases affecting the interstitium (the tissue and space around the air sacs of the lungs). It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage. But in interstitial lung disease, the repair process goes awry and the tissue around the air sacs (alveoli) becomes scarred and thickened. This makes it more difficult for oxygen to pass into the bloodstream. The term ILD is used to distinguish these diseases from obstructive airways diseases.

In children, several unique forms of ILD exist which are specific for the young age groups. The acronym chILD is used for this group of diseases and is derived from the English name, Children’s Interstitial Lung Diseases – chILD.

Prolonged ILD may result in pulmonary fibrosis, but this is not always the case. Idiopathic pulmonary fibrosis is interstitial lung disease for which no obvious cause can be identified (idiopathic), and is associated with typical findings both radiographic (basal and pleural based fibrosis with honeycombing) and pathologic (temporally and spatially heterogeneous fibrosis, histopathologic honeycombing and fibroblastic foci).

In 2013 interstitial lung disease affected 595,000 people globally. This resulted in 471,000 deaths.

Restrictive lung diseases (or restrictive ventilatory defects) are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation. Pulmonary function test demonstrates a decrease in the forced vital capacity.

To date there have been no clinical trials to determine effective treatment for this disease. Some patients have been treated with somatostatin analogs. Although the cough associated with DIPNECH tends to diminish on this treatment, improvement in pulmonary function has not been clearly demonstrated. There are also reports of symptomatic treatment with long- and short-acting beta agonists. Although steroids, both oral and inhaled, have been used in the setting of DIPNECH, there is no clear improvement with this treatment.

It is not uncommon for typical carcinoids to arise within DIPNECH. Due to presence of these tumors, DIPNECH is classified as a pre-malignant condition. Although there have been reports of atypical carcinoids with local lymph node involvement, there are no reports of more aggressive neuroendocrine tumors, such as large cell neuroendocrine or small cell lung cancer, associated with DIPNECH. When isolated bronchial carcinoids are diagnosed, oncology guidelines recommend surgical resection with lymph node sampling. However, as multiple carcinoids may develop in the setting of DIPNECH, a more conservative approach is often considered to preserve lung function.

The morbidity associated with DIPNECH is due to the associated obstructive lung disease. The lung disease tends to be slowly progressive, but given enough time can lead to significant disability and require supplemental oxygen therapy. There have been reports of lung transplantation in the setting of end-stage DIPNECH.

Macrolide antibiotics, such as erythromycin, are an effective treatment for DPB when taken regularly over an extended period of time. Clarithromycin or roxithromycin are also commonly used. The successful results of macrolides in DPB and similar lung diseases stems from managing certain symptoms through immunomodulation (adjusting the immune response), which can be achieved by taking the antibiotics in low doses. Treatment consists of daily oral administration of erythromycin for two to three years, an extended period that has been shown to dramatically improve the effects of DPB. This is apparent when an individual undergoing treatment for DPB, among a number of disease-related remission criteria, has a normal neutrophil count detected in BAL fluid, and blood gas (an arterial blood test that measures the amount of oxygen and carbon dioxide in the blood) readings show that free oxygen in the blood is within the normal range. Allowing a temporary break from erythromycin therapy in these instances has been suggested, to reduce the formation of macrolide-resistant "P. aeruginosa". However, DPB symptoms usually return, and treatment would need to be resumed. Although highly effective, erythromycin may not prove successful in all individuals with the disease, particularly if macrolide-resistant "P. aeruginosa" is present or previously untreated DPB has progressed to the point where respiratory failure is occurring.

With erythromycin therapy in DPB, great reduction in bronchiolar inflammation and damage is achieved through suppression of not only neutrophil proliferation, but also lymphocyte activity and obstructive mucus and water secretions in airways. The antibiotic effects of macrolides are not involved in their beneficial effects toward reducing inflammation in DPB. This is evident because the treatment dosage is much too low to fight infection, and in DPB cases with the occurrence of macrolide-resistant "P. aeruginosa", erythromycin therapy still reduces inflammation.

A number of factors are involved in suppression of inflammation by erythromycin and other macrolides. They are especially effective at inhibiting the proliferation of neutrophils, by diminishing the ability of interleukin 8 and leukotriene B4 to attract them. Macrolides also reduce the efficiency of adhesion molecules that allow neutrophils to stick to bronchiolar tissue linings. Mucus production in the airways is a major culprit in the morbidity and mortality of DPB and other respiratory diseases. The significant reduction of inflammation in DPB attributed to erythromycin therapy also helps to inhibit the production of excess mucus.

Untreated DPB leads to bronchiectasis, respiratory failure, and death. A journal report from 1983 indicated that untreated DPB had a five-year survival rate of 62.1%, while the 10-year survival rate was 33.2%. With erythromycin treatment, individuals with DPB now have a much longer life expectancy due to better management of symptoms, delay of progression, and prevention of associated infections like "P. aeruginosa". The 10-year survival rate for treated DPB is about 90%. In DPB cases where treatment has resulted in significant improvement, which sometimes happens after about two years, treatment has been allowed to end for a while. However, individuals allowed to stop treatment during this time are closely monitored. As DPB has been proven to recur, erythromycin therapy must be promptly resumed once disease symptoms begin to reappear. In spite of the improved prognosis when treated, DPB currently has no known cure.

Alveolar lung diseases, are a group of diseases that mainly affect the alveoli of the lungs.

Obstructive lung disease is a category of respiratory disease characterized by airway obstruction. Many obstructive diseases of the lung result from narrowing (obstruction) of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, problems exhaling and frequent medical clinic visits and hospitalizations. Types of obstructive lung disease include; asthma, bronchiectasis, bronchitis and chronic obstructive pulmonary disease (COPD). Although COPD shares similar characteristics with all other obstructive lung diseases, such as the signs of coughing and wheezing, they are distinct conditions in terms of disease onset, frequency of symptoms and reversibility of airway obstruction. Cystic fibrosis is also sometimes included in obstructive pulmonary disease.

Respiratory disease is a common and significant cause of illness and death around the world. In the US, approximately 1 billion "common colds" occur each year. A study found that in 2010, there were approximately 6.8 million emergency department visits for respiratory disorders in the U.S. for patients under the age of 18. In 2012, respiratory conditions were the most frequent reasons for hospital stays among children.

In the UK, approximately 1 in 7 individuals are affected by some form of chronic lung disease, most commonly chronic obstructive pulmonary disease, which includes asthma, chronic bronchitis and emphysema.

Respiratory diseases (including lung cancer) are responsible for over 10% of hospitalizations and over 16% of deaths in Canada.

In 2011, respiratory disease with ventilator support accounted for 93.3% of ICU utilization in the United States.

In disorders that are intrinsic to the lung parenchyma, the underlying process is usually pulmonary fibrosis (scarring of the lung). As the disease progresses, the normal lung tissue is gradually replaced by scar tissue interspersed with pockets of air. This can lead to parts of the lung having a honeycomb-like appearance.

Alveolar lung disease may be divided into acute or chronic. Causes of acute alveolar lung disease include pulmonary edema (cardiogenic or neurogenic), pneumonia (bacterial or viral), pulmonary embolism, systemic lupus erythematosus, bleeding in the lungs (e.g., Goodpasture syndrome), idiopathic pulmonary hemosiderosis, and granulomatosis with polyangiitis.

Chronic alveolar lung disease can be caused by pulmonary alveolar proteinosis, alveolar cell carcinoma, mineral oil pneumonia, sarcoidosis (alveolar form), lymphoma, tuberculosis, metastases, or desquamative interstitial pneumonia.

Diagnosis of obstructive disease requires several factors depending on the exact disease being diagnosed. However one commonalty between them is an FEV1/FVC ratio less than 0.7, i.e. the inability to exhale 70% of their breath within one second.

Following is an overview of the main obstructive lung diseases. "Chronic obstructive pulmonary disease" is mainly a combination of chronic bronchitis and emphysema, but may be more or less overlapping with all conditions.