PDE4 Inhibitors and Methylxanthines

Phosphodiesterase-4 inhibitors (PDE4 inhibitors) and methylxanthines are 2 types of drugs. Both may be used to treat people with chronic obstructive pulmonary disease (COPD).¹

People with COPD often face irritated and inflamed airways, making them too narrow for enough air to pass in and out of the lungs. Sometimes, the irritation can cause the band of muscles surrounding the airways to tighten, narrowing the airways. This is called a bronchospasm. Bronchospasms often happen during COPD flare-ups.²

Medicines called bronchodilators and steroids are commonly used to help ease these symptoms. But some people may need to use other drugs when bronchodilators and steroids do not work. These other drugs include PDE4 inhibitors and methylxanthines.¹

How do PDE4 inhibitors work?

PDE4 inhibitors work by helping to reduce swelling in the airways. PDE4 is a type of enzyme that is involved in the inflammatory response. In people with COPD, there is too much inflammation in the airways, making breathing difficult. PDE4 inhibitors block the enzyme and can help reduce the inflammation.⁴

PDE4 inhibitors, such as Daliresp® (roflumilast), can be helpful for people who cannot tolerate the side effects of steroids. They reduce swelling in a different way than steroids do. Daliresp is taken daily as a pill alongside a bronchodilator, especially for people with severe COPD. Daliresp can help to reduce the number of flares they have per year.^4,5

While PDE4 inhibitors cannot treat sudden or severe COPD symptoms, they serve as maintenance therapy to reduce flare-ups when taken consistently.^4,5

What are the possible side effects of PDE4 inhibitors?

Side effects can vary depending on the specific drug you are taking. The most common side effects of PDE4 inhibitors include:^4,5

• Headache
• Back pain
• Dizziness
• Decreased appetite
• Nausea
• Diarrhea
• Weight loss
• Flu-like symptoms
• Difficulty sleeping (insomnia)

PDE4 inhibitors may cause severe side effects, including suicidal thoughts or behaviors. You should seek medical attention if you experience:⁵

• Thoughts of self-harm
• Increased depression or anxiety
• Unusual changes in behavior or mood

These are not all the possible side effects of PDE4 inhibitors. Talk to your doctor about what to expect when taking PDE4 inhibitors. You also should call your doctor if you have any changes that concern you when taking PDE4 inhibitors.

How do methylxanthines work?

Methylxanthines reduce swelling in the airways and relax the bands of muscles around the airways. The most common type of methylxanthine is called theophylline.⁶

While less commonly used due to newer and more effective bronchodilators, methylxanthines can be an option for those not finding relief from other bronchodilators.⁶

What are the possible side effects of methylxanthines?

Side effects can vary depending on the specific drug you are taking. The most common side effects of methylxanthines include:⁶

• Nausea
• Diarrhea
• Headache
• Stomach pain
• Restlessness
• Irritability
• Difficulty sleeping

Methylxanthines can also cause more serious side effects. These include:⁶

• Vomiting
• Irregular or rapid heartbeat
• Seizures
• Skin rash

These are not all the possible side effects of methylxanthines. Talk to your doctor about what to expect when taking methylxanthines. You also should call your doctor if you have any changes that concern you when taking methylxanthines.

Other things to know

It is crucial to take the correct amount of methylxanthine medicine to avoid severe side effects. Taking other types of medicines at the same time can also make side effects more likely.⁶

Before beginning treatment for COPD, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.