Xanthines

Methylxanthines are found in high concentrations in tea, coffee, and chocolate. They have a modest bronchodilator effect although not as effective as other bronchodilators and corticosteroids. Theophylline is reported to improve inspiratory muscle function, specifically the diaphragm, and may have some anti-inflammatory effects. However it is more likely to cause side effects and interactions with other drugs.

The effects are not felt straight away and therefore it should not be used to relive sudden shortness of breath or wheeze. They are considered ‘add on’ therapy in asthma if symptoms are not well controlled despite medium dose inhaled steroids and long acting bronchodilators in asthma and COPD.

Whichever brand of Xanthine is used the patient should remain on the same brand of preparation throughout their treatment.

Drug name:

  • Aminophylline - Intravenous.
  • Theophylline – oral preparations Slo-Phyllin®, Nuelin SA®, UniphyllinContinus®.

Side effects:

  • Insomnia.
  • Nausea.
  • Vomiting.
  • Fast/ slow/ irregular heartbeat.
  • Seizures.
  • Occasionally patients can feel irritable and restless.

Side effects are dose-dependent. Blood levels of theophylline should be monitored to ensure a therapeutic level but they are affected by age, liver disease, congestive heart failure and many drug interactions. Cigarette smoking decreases effectiveness and caffeine and alcohol can increase levels of methylxanthines. Caffine and alcohol can increase the side effects of this medication. Avoid drinking large amounts of beverages containing alcohol or caffine (such as coffee, tea, cola), eating large amounts of chocolate or taking nonprescription products that contain caffine.

A dose that is too little does not give any benefit and a dose that is too high causes significant side effects. Theophylline has modest clinical benefits and is not recommended as a first line drug. However, it can serve as an alternative for patients who are intolerant of LABAs and LAMAs.