Medical treatment

MEDICATIONS

The European protocol has endorsed specific drugs for treating pulmonary arterial hypertension:

• Endothelin Receptor Antagonists (ERA)

These medications aim to counteract the adverse effects of endothelin, a substance believed to be excessively produced in patients with pulmonary arterial hypertension (PAH), leading to vasoconstriction (narrowing) of blood vessels.

Two ERA drugs approved for PAH treatment in Europe include:

1. Bosentan
2. Tracleer
3. Ambrisentan

ERAs are administered orally.

• Phosphodiesterase Type-5 (“PDE-5”) Inhibitors

Inhibiting PDE-5 enzymes induces vasodilation through nitric oxide. Additionally, PDE-5 inhibitors exhibit an antiproliferative effect.

Two PDE5 inhibitors approved for PAH treatment in Europe are:

1. Sildenafil (Viagra, Revatio)
2. Tadalafil PDE-5 inhibitors are oral medications.

• Prostanoids

Prostacyclin exerts a potent vasodilator effect, and its clinical use is made possible through synthetic analogs.

Three prostanoids approved for use in Europe are:

1. Iloprost (Ventavis)
2. Treprostinil
3. Epoprostenol

Prostanoids are administered through inhalation (iloprost), subcutaneously (treprostinil), or intravenously (epoprostenol).

Instructions for using the Omron nebulizer

As part of the Venta Care support program for pulmonary hypertension patients, BAYER has prepared detailed instructions to guide the correct use of the OMRON microAIR nebulizer for inhalation with Ventavis.

In conjunction with the primary treatment, it is essential to implement general therapy, including:

• Calcium Channel Blockers (CCBs)

Considered first-line drugs in pulmonary hypertension treatment, calcium channel blockers offer a straightforward and cost-effective long-term approach. As per S. Rich et al. (1992), a positive response to such therapy results in a 95% five-year survival rate.

The mechanism of calcium channel blockers (calcium antagonists) involves inhibiting the passage of calcium ions into heart and blood vessel cells. This effect leads to a reduction in smooth muscle tone in the vascular wall, decreased force of myocardial contraction, lower oxygen demand in the contracting heart, and increased coronary blood flow. These drugs find common use in pulmonary hypertension treatment.

CCBs are typically prescribed one to three times a day, and some are administered intravenously, often in a hospital setting, to control heart rate and blood pressure. Commonly prescribed medications for pulmonary hypertension patients include nifedipine, diltiazem, and amlodipine.

While CCBs were previously more widely used for PH treatment, recent studies indicate their suitability for a small proportion of patients (less than 10%). CCBs are generally reserved for patients with PH who have exhibited a positive response during right heart vasodilator catheterization.

Experts recommend administering these medications cautiously, with dose increases made only as tolerated. Especially with CCBs from the verapamil group, which predominantly affect the heart, electrocardiographic monitoring is crucial. Side effects may include headache, dizziness, facial flushing, heat sensations (“hot flashes”), a sudden drop in blood pressure, and swelling of the legs and arms.

• Digoxin

Digoxin enhances heart contraction efficiency, reduces myocardial oxygen demand, lowers heart rate, and inhibits excitation conduction. Its use for PH is approached with great care and is limited to cases of decompensated right ventricular failure due to the risk of arrhythmogenic effects. Side effects, particularly in larger doses, may include various heart rhythm disturbances, gastrointestinal issues, weakness, fatigue, and visual disturbances.

Digoxin interactions with other medications are possible, and blood tests to determine digoxin levels aid in determining the appropriate dose and preventing side effects.

• Warfarin (Anticoagulants)

Oral anticoagulants (OAC) are prescribed in PH patients due to risk factors for venous thromboembolism, like heart failure and sedentary lifestyle. Warfarin, which thins the blood to prevent clotting, may lead to hemorrhage as a common side effect.

Strict adherence to the prescribed warfarin dose is crucial, with daily doses taken at the same time. Blood tests determine the warfarin dose, with the target international normalized ratio (INR) for primary PH set at 1.5-2.5. Individual assessments based on the risk-to-effectiveness ratio should guide the decision to prescribe warfarin for other forms of PH.

Crucial Information:

Warfarin Interactions: Warfarin interacts with various drugs, influencing its effectiveness. Therefore, patients should consult their doctor before adding any new medication to an existing regimen that includes warfarin. Doctors must thoroughly review new medication instructions for potential interactions with warfarin, and when in doubt, monitor INR more frequently.

• Diuretics

Diuretics, commonly known as water pills, facilitate the removal of excess fluid from the body. This action reduces the volume of circulating blood, leading to lowered blood pressure and decreased cardiac load—an essential aspect of PH treatment. Despite their effectiveness, improper prescription and use of diuretics can result in significant problems. Diuretics cause the removal of salts, particularly potassium and calcium, along with excess fluid. This can lead to heart and kidney dysfunction, including dehydration, low blood pressure, and chemical imbalances in the blood. Regular monitoring of blood pressure and kidney function is crucial for patients taking diuretics.

In the 1990s, it was discovered that even low doses of diuretics, equivalent to no more than 25 mg of dichlorothiazide (a common diuretic drug), per day, proved effective for patients. This reduced dosage minimized side effects significantly while maintaining therapeutic benefits.

• Oxygen Therapy

Oxygen, a vital element in all body energy processes, plays a key role in ensuring normal bodily functions. Oxygen administration is recommended for all forms of pulmonary hypertension. It diminishes hypoxia and, consequently, reduces vasoconstriction (narrowing) of small vessels.

Oxygen therapy is a critical life-saving treatment for pulmonary hypertension. It involves breathing pure oxygen to compensate for cellular oxygen deficiency. Unlike many modern therapies, oxygen therapy is entirely safe, with virtually no contraindications or allergic reactions. It's important to note that patients with pulmonary hypertension often require long-term, sometimes lifelong, oxygen therapy, administered through inhalation.