Pulmonary arterial hypertension (PAH) is high blood pressure in the lungs. It is a condition when there is increased pressure in the vessels caused by an obstruction in the small arteries in the lung for a variety of reasons. Such complexities might arise from various reasons. However, there are effective generic medications like Tadalafil, that are helping patients across the globe. Let us see how this medication plays a major role in addressing pulmonary hypertension. 

Salient Features of Tadalafil 

• Tadalafil is the strongest vasodilation medication among the other phosphodiesterase type 5 (PDE5) inhibitors. 
• It is associated with the treatments of Erectile Dysfunction (ED) or impotency in men, hypertension, or NYHA Functional Class II-III Pulmonary arterial hypertension (PAH). 

How does Tadalafil work for Pulmonary Hypertension?

Phosphodiesterase type 5 (PDE5) is an enzyme that is produced in various parts of the body and which breaks down another substance called cyclic guanosine monophosphate (GMP). Cyclic GMP causes the blood vessels or arteries to relax and open up. 

Studies have shown that being a PDE5 inhibitor, Tadalafil decreases the activity of PDE5 so that more cyclic GMP is available for the blood vessels inside the lungs. This eventually leads to the relaxation or widening of those blood vessels or arteries. 

Further, this relaxing and widening of the blood vessels in the lungs decreases the pulmonary blood pressure to the heart and improves its function. Research studies have already verified this improvement.

What is the daily Tadalafil dosage for Pulmonary Hypertension? 

The usual recommended dose of Tadalafil for the treatment of pulmonary arterial hypertension is 40 mg (once) or even two 20 mg tablets (at two phases) daily, with or without food. 

However, doctors may suggest starting with one tablet a day and then advancing to the full dose of two tablets daily to allow the patient to adjust to the medication, as per his or her condition. This is why it is important to be under the constant monitoring of a doctor. 

According to a report, in mild or moderate liver disease (Child-Pugh Class A or B), one should consider starting tadalafil at a dose of 20 mg once daily. In severe liver disease (Child-Pugh Class C), it is generally recommended to avoid use.

In patients with mild-to-moderate kidney disease (having creatinine clearance 31 to 80 ml/min), it is recommended to start tadalafil at 20 mg once daily and to increase to 40 mg once daily based on individual tolerability. 

However, in patients with severe kidney disease (with creatinine clearance < 30 ml/min or on dialysis), it is recommended to avoid the use of tadalafil. This is because severe kidney disease increases the amount of tadalafil in the bloodstream, even in patients on dialysis. Also, there is limited assurance of using Tadalafil in these patients.

Further, Tadalafil is not recommended in patients with either of the two rare conditions, i,e pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis.

What are the probable side effects of using Tadalafil for Pulmonary Hypertension? 

There are some side effects that need immediate medical attention, such as:

• Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
• Hearing loss or ringing in ears
• Heart attack—pain or tightness in the chest, shoulders, arms, or jaw, nausea, shortness of breath, cold or clammy skin, feeling faint or lightheaded
• Low blood pressure—dizziness, feeling faint or lightheaded, blurry vision
• Prolonged or painful erection
• Redness, blistering, peeling, or loosening of the skin, including inside the mouth
• Stroke—sudden numbness or weakness of the face, arm, or leg, trouble speaking, confusion, trouble walking, loss of balance or coordination, dizziness, severe headache, change in vision
• Sudden vision loss in one or both eyes

However, there are also some side effects that ease out with time and usually do not require medical attention, such as the followings:

• Back pain
• Facial flushing or redness
• Headache
• Muscle pain
• Runny or stuffy nose
• Upset stomach

This list may not describe all possible side effects. A licensed medical expert might help best in this regard. 

What to share with a doctor before taking this medication?

Doctors need to know if the patient is having any of the following conditions:

• Eye or vision problems, including a rare inherited eye disease called retinitis pigmentosa
• Heart disease, angina, a history of heart attack, irregular heartbeats, or other heart problems
• High or low blood pressure
• Kidney disease
• Liver disease
• Pulmonary Veno-occlusive disease (PVOD)
• Stomach ulcers
• Stroke
• An unusual or allergic reaction to tadalafil, other medications, foods, dyes, or preservatives
• Pregnant or trying to get pregnant
• Breast-feeding