Important advances in the treatment of pulmonary hypertension have dramatically improved the prognosis for patients. As a result, mortality from PH has fallen significantly in the past several years. The quality of life of patients suffering from the condition has also markedly improved.

When the diagnosis is secondary pulmonary hypertension, SPH, doctors can sometimes treat the underlying cause and relieve pulmonary hypertension. In the case of SPH caused by small blood clots in the lungs, for instance, it may be possible to eliminate the clots, with either medication or surgery. If the underlying cause is AIDS, anti-HIV drugs may help improve blood pressure in the pulmonary arteries. Autoimmune diseases such as scleroderma and lupus can also lead to SPH. In such cases, drugs that suppress an overactive immune system, such as corticosteroids, can help.

Sometimes, however, doctors can do little to treat the underlying condition. In that case, and when there is no identifiable cause, the approach is to treat the high blood pressure and its consequences. Fortunately, doctors have a growing arsenal of drugs that can help. Here are a few of the most commonly prescribed medications:

These drugs, taken in pill form, help relax the muscles in the walls of blood vessels, causing them to open wider and thus reduce pulmonary blood pressure. Calcium channel blockers have been shown to prolong life in about 20 percent of patients with primary pulmonary hypertension. Unfortunately, calcium channel blockers will decrease blood pressure in the rest of the body, which can cause problems, so they must be prescribed with caution. There is no simple way for doctors to predict which patients will respond to oral calcium channel blockers. Physicians often test whether patients will benefit from these drugs during a right heart catheterization, which is used to measure pulmonary blood pressure. Patients are given a short-acting drug before or during the procedure. Patients who react well to the drug are the best candidates for long-term oral calcium channel therapy.

Like most effective drugs, calcium channel blockers have side effects. These can include fatigue, dizziness, headache, heartburn, constipation, and swelling of the abdomen, ankles, or feet. Less common side effects include fainting spells (also called syncope), very slow or very fast heartbeats, and liver damage. If you experience side effects while taking calcium channel blockers, notify your doctor immediately. Calcium channel blockers include amlodipine (Norvasc), diltiazem (Cardizem, Tiazac), nifedipine (Adalat, Procardia), and felodipine (Plendil).

This class of drugs is derived from substances that the cells lining blood vessel walls manufacture naturally. In medication form, prostacyclins have been shown to dilate, or open up, the pulmonary arteries, easing blood pressure. They also make blood in the pulmonary arteries less sticky, which may help prevent blood clots from forming. Studies show that prostacyclin can increase exercise tolerance, improve symptoms, and prolong life in patients with primary pulmonary hypertension, as well as those who have pulmonary hypertension associated with a known cause (secondary pulmonary hypertension). In certain cases, patients have been on the drug for 10 years or more and continue to benefit. Several different kinds of prostacyclins have been developed, which are administered in different ways. They include the following:

•Epoprostenol (Flolan). The first approved prostacyclin, epoprostenol has been shown to lower pulmonary blood pressure. As a result, patients experience less shortness of breath, improved ability to exert themselves, improved quality of life, and improved survival rates. Because epoprostenol only remains in the blood for a few minutes, it must be continuously infused through an intravenous catheter attached to a small pump that is worn in a pack on the shoulder or belt. Taking the drug requires that patients prepare the medication mixture, operate the pump, and maintain the intravenous catheter. And there are side effects, including jaw pain, nausea, diarrhea, leg cramps, and foot pain. Because the drug requires an IV, there is also the risk of infection at the site. Yet epoprostenol helps many people with pulmonary hypertension, particularly those with more advanced cases, lead more active and more comfortable lives.

•Treprostinil (Remodulin). This newly approved form of prostacyclin can be delivered subcutaneously, or just under the skin. It is administered by a small pump that is worn on the belt. Like other prostacyclins, treprostinil helps relax the muscles in blood vessels, allowing them to widen and increase the supply of blood to the lungs. Pain at the infusion site is very common, in addition to the other side effects seen with the intravenous form of a prostacyclin, epoprostenol.

•Iloprost (Ventavis). This drug is a form of prostacyclin that comes in an inhaled aerosolized form. Studies have shown that it can improve right heart function and pulmonary blood pressure. Because the drug is short-acting, frequent inhalations are necessary. Side effects, like coughing, are minor. More information is needed, however, before this medication can be routinely recommended. It is currently only available in the United States if you participate in a clinical trial.

This class of drugs was developed after researchers noticed that many patients with pulmonary hypertension had abnormally elevated levels of a substance called endothelin-1. High levels of endothelin-1 are one reason that blood vessels become stiff and unable to widen properly. Substances that block endothelin-1, called antagonists, have been shown to improve stamina and provide relief of symptoms in patients with some forms of pulmonary hypertension.

The first drug in this class to be approved by the FDA is bosentan (Tracleer). Side effects associated with the drug include nasal stuffiness, flushing, headaches, and abnormal elevation of liver function tests. Patients prescribed bosentan should have their liver function monitored, by way of a simple blood test, every month. Liver function tests typically return to normal when the drug is discontinued. Based on studies done in animals, Bosentan is expected to cause fetal harm if given to pregnant women. This medication should be given to women of childbearing age only after they test negative for pregnancy and agree to practice contraception while taking the drug.

Better known as Viagra, the erectile dysfunction drug, sildenafil has emerged as an important new therapy for pulmonary hypertension. The drug relaxes smooth muscle cells, allowing arteries to widen, thus decreasing blood pressure.

This substance is produced by cells in the artery to control widening, or vasodilation. Used as a drug, nitric oxide has been shown to relieve pulmonary hypertension in newborns when inhaled.

Drugs that thin the blood, such as warfarin (Coumadin), are prescribed to prevent blood clots from forming in the lungs. People with pulmonary hypertension are at heightened risk of blood clots because of sluggish blood flow, enlarged right heart chambers, and physical inactivity, among other factors. Warfarin is also used in people with pulmonary hypertension caused by blood clots.

This drug is sometimes prescribed to slow heartrate and strengthen the contraction of the right part of the heart, enabling it to pump more blood with each beat. The long-term consequences of using the drug for PH are unknown.

Because low oxygen levels are known to cause pulmonary hypertension, and pulmonary hypertension can also lead to low oxygen levels, supplemental oxygen can often help relieve the disease. The oxygen is supplied through a narrow tube placed in the nose (called a nasal cannula). This is helpful in all patients who have low oxygen levels, regardless of whether low oxygen is the cause or the result of the pulmonary hypertension.

These medications, commonly known as "water pills," help rid the body of excess fluid. This can help reduce the strain on the heart. Diuretics are also used to reduce fluid buildup in the legs, feet, and lungs.

Because different drugs act in different ways, doctors often prescribe several drugs to patients with pulmonary hypertension. Your physician may prescribe calcium channel blockers to reduce pulmonary blood pressure, for instance, and a blood-thinning drug to prevent the formation of new blood clots. Ongoing research is helping experts zero in on the most effective combinations. For example, in 2003, German researchers at Justus-Liebig University in Giessen reported that a combination of inhaled iloprost and sildenafil appeared to provide extra benefit to patients with severe pulmonary hypertension.

Researchers are also investigating "alternative" treatments. One that has sparked interest is L-arginine, which is available in many health food stores as a nutritional supplement. L-arginine is a precursor of nitric oxide. In one small study, 19 patients who took L-arginine supplements saw decreases in their pulmonary blood pressure and increases in oxygen. Experts caution against taking nutritional supplements without talking to your doctor first, however, since some have been shown to interact dangerously with prescription medications. Also, supplements like L-arginine are largely unregulated, research on them is scant and, of the research that does exist, some is less than promising. One 2006 clinical trial, funded by the National Institutes of Health, found an increased risk of death in patients with previous heart problems who used L-arginine. You should always let your doctor know all the over-the-counter and prescription drugs you take, because some medications for pulmonary hypertension interact with a variety of other drugs.

-- Peter Jaret is a contributing editor for Health magazine and a winner of the American Medical Association's award for medical reporting. His work has appeared in National Geographic, Newsweek, Hippocrates, and many other national magazines. He is also the author of In Self-Defense (Harcourt Brace Jovanovich), Active Living Every Day, and Heart Healthy for Life.

References

First published October 27, 2003
Last updated October 30, 2007
Copyright © 2003 Consumer Health Interactive

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