What is theophylline?
Theophylline is a drug used in the treatment of respiratory diseases. It is usually taken orally in tablet, capsule, or liquid form, although it can also be injected intravenously. Theophylline is sold under several brand names, including:
It belongs to a class of drugs called methylxanthines.
Theophylline is used mainly for treating respiratory and lung diseases including asthma, bronchospasm, and COPD (bronchitis and emphysema).
‘Smooth’ muscle is found on the walls of hollow organs. When smooth muscle in your airway tightens, it can cause symptoms such as wheezing, chest tightness, and breathlessness. Constriction of airway smooth muscle is a major characteristic of airflow obstruction in both asthma and COPD.
Theophylline is the most well known and most commonly used methylxanthine. At low dosages, it has an immunomodulatory, anti-inflammatory, and bronchoprotective effect (meaning it protects against bronchoconstriction: the tightening of your airway). Higher doses are needed for its bronchodilator effect (which causes airway expansion).
Other methylxanthines include aminophylline, oxtriphylline, and dyphylline.
What does theophylline do?
Theophylline is used to treat and prevent the symptoms of asthma, bronchitis, emphysema, and other lung diseases or breathing problems such as wheezing, chest tightness, or shortness of breath.
Theophylline may also be used in treating breathing problems in premature infants.
What is the mechanism of action of theophylline?
Theophylline has two distinct actions in the airways of patients.
Firstly, it works by relaxing the smooth muscles in the lungs and opening up breathing airways for air to flow through more easily (i.e., bronchodilation).
And secondly, it makes the lungs less sensitive to allergens and other triggers that lead to the narrowing of the bronchi (bronchospasm).
Theophylline inhibits type III and type IV phosphodiesterase (PDE), the enzyme responsible for breaking down cyclic AMP in smooth muscle cells and involved in inflammatory processes in both asthma and COPD.
Cyclic AMP plays an important role in regulating the contraction of airways smooth muscles. So increased levels of cyclic AMP can help lead to bronchodilation and muscle relaxation.
Theophylline also binds to the adenosine A2B receptor and blocks adenosine-mediated bronchoconstriction.
How long does it take for theophylline to work?
Theophylline is rapidly and completely absorbed after oral administration in solution or immediate-release solid oral dosage form.
Six weeks is long enough to tell if theophylline works.
If theophylline has had no effect after you've been taking it for six weeks or more, then it is probably not the right medication for you. You and your doctor might need to discuss other treatment options available.
What are the most common side effects of theophylline?
Some of the very common and less serious side effects may include:
- Stomach pain, diarrhea
- Increased urination
- Feeling restless, nervous, or irritable
If any of these effects last too long or are severe, tell your doctor as soon as possible.
Stop using theophylline and get medical help immediately if you have a serious side effect such as:
- Severe or continued vomiting or nausea
- Rapid or uneven heartbeats
- Seizure (convulsions)
- Confusion, tremors or shaking
- Severe headaches
- High blood sugar (increased thirst, increased urination, hunger, dry mouth, drowsiness, blurred vision, weight loss)
Allergic reactions to theophylline are rare.
Nevertheless, get emergency medical help if you notice any signs of allergic reactions such as hives; swelling of your face, lips, tongue, or throat; severe dizziness, trouble breathing; rash/itching.
This is not a complete list of side effects and others may occur. Talk to your doctor for medical advice about side effects.
What are the symptoms of theophylline toxicity?
Theophylline overdose can occur if you accidentally take too much at one time. Overdose can also occur slowly over time if your daily doses are too high.
It is recommended not to take theophylline longer than needed.
To be sure you are using the correct dose, your blood will need to be tested often by your doctor.
Overdose symptoms may include severe forms of some of the side effects listed above like passing out, seizures, arrhythmias, or trouble breathing.
Seek emergency medical help if toxicity occurs due to overdose.
What are normal theophylline levels?
You will need to be tested to determine the concentration of theophylline in your blood to establish an appropriate dose, to maintain a therapeutic level, and to evaluate toxic concentrations.
The therapeutic concentration for theophylline, when used as a bronchodilator, is generally considered to be 5–15 mcg/mL for adults, 5–10 mcg/mL for children and neonates. Levels greater than 20 mcg/mL are considered toxic.
Some people may experience significant side effects at concentrations of less than 20 mcg/mL. When theophylline is used to treat apnea in premature neonates, the therapeutic range is 6-11 mcg/mL.
Low levels of theophylline and caffeine may indicate that the drug has not reached a therapeutic level for the individual tested and there is insufficient drug present to be effective.
Blood levels in the therapeutic range mean that most people will have their symptoms relieved without experiencing significant side effects. Adverse side effects and the risk of seizures increases with higher concentrations of theophylline.
The use of theophylline as a bronchodilator has decreased over the years as other more effective and less toxic treatments for asthma and COPD have become available. However, It is still in use in some countries but usually not as the first choice of treatment.
What is the correct dosage of theophylline and how should it be taken?
Theophylline comes in the form of tablets, capsules, oral elixirs, and intravenous solutions at different strengths usually taken once or twice daily.
The dose and the number of times you take theophylline daily will depend on the reason you are taking it, your medical condition, response to treatment, age, weight, lab tests (theophylline blood levels), and other medications you may be taking.
For asthma treatment, theophylline is prescribed as an ‘add on’ treatment to your usual medication.
There are two kinds of theophylline medicines: One is for you to take at home (usually as a tablet or capsule) to help manage your day-to-day asthma symptoms. The other is an emergency medicine that is only given at the hospital.
Take theophylline exactly as directed or prescribed by your doctor.
Do not crush or chew the capsules or tablets as doing so can release all of the medicine at once and increase the risk of side effects.
Likewise, do not split the tablets unless they have a score line and your doctor tells you to do so. Swallow the whole or split tablet without crushing or chewing.
Talk to your doctor about whether you should take theophylline with food or on an empty stomach. Both options are generally considered safe, but it is recommended that you are consistent in taking theophylline either without food or on an empty stomach, rather than alternating between the two.
To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor’s instructions carefully.
You will need regular medical tests to be sure you are using the right dose.
Theophylline controls symptoms of asthma and other lung diseases but does not cure them. Continue to take theophylline even if you feel well.
Do not stop taking theophylline or change your medication dose/schedule without talking to your doctor.
What time should I take theophylline?
Since different manufacturers have different ways to take theophylline, ask your doctor about the best time to take your brand of theophylline and if you should take it with or without food.
Take theophylline regularly, around the same time every day to get the most benefit out of it.
To help you remember, take it at the same time(s) each day or try linking it to a daily habit, for example, if you need to take it once a day, take it while you’re making your first cup of tea/coffee in the morning.
How long does theophylline stay in your system?
A drug stays in your body for approximately 5.5 x the elimination half-life of that particular drug.
Theophylline has a half-life of about 8 hours.
It will, therefore, take approximately 2 days (about 44 hours) for theophylline to be cleared from your system.
What medications interact with theophylline?
Some medicines can affect how theophylline works and theophylline could also affect how other medicines work, making them less effective or causing side effects.
Many drugs can interact with theophylline. Tell your doctor about all medications/products you use, start using, or stop using while you’re on your treatment with theophylline, especially the following:
- Heart or blood pressure medications
- Heart rhythm medication such as Mexiletine or Propafenone
- Medications to treat kidney stones
- Seizure medication
This is not a complete list of all possible drug interactions and many other drugs can interact with theophylline.
Minor drug interactions do not usually cause harm or require a change in therapy. However, your doctor can determine if adjustments to your medications are necessary.
Do not start, stop, or change the dosage of any medicines without your doctor’s approval. check with your physician if you have any concerns.
What foods shouldn’t I eat while taking theophylline?
Certain diets (such as high protein/low carbohydrate or high carbohydrate/low protein) may change the effect of theophylline.
Tell your doctor if you have any major changes in your diet. Your doctor may need to adjust your dose.
Ask your doctor before using theophylline together with caffeine. Using these together may increase some of the side effects of theophylline. This can cause nausea, vomiting, insomnia, tremors, restlessness, uneven heartbeats, and seizure (convulsions).
Avoid or limit your consumption of drinks or foods that contain caffeine, such as coffee, tea, cola, and chocolate.
Avoid eating foods that are high in fat within one hour before or after taking theophylline and minimize fatty foods generally in your diet, as it can increase the bioavailability of theophylline and thus make it more potent.
If you have any questions or concerns regarding your diet, or about foods and drinks that may interact with theophylline, you should discuss them with your doctor.
Is theophylline safe during pregnancy or when breastfeeding?
It is not known whether theophylline will harm an unborn baby.
Theophylline should be used only when really needed during pregnancy. Discuss the risks and benefits with your doctor.
Tell your doctor if you are pregnant or plan to become pregnant while using this medication.
Theophylline can pass into breast milk and may have some effects on a nursing infant. Do not use this medication without telling your doctor if you are breastfeeding a baby.
Can I drink alcohol while taking theophylline?
It is recommended that you limit the intake of alcoholic beverages in large amounts while taking theophylline.
Combining alcohol and theophylline may increase the risk of side effects.
Discuss with your doctor the use of theophylline with alcohol and follow the advice you’re given.
What else should I know before taking theophylline?
You should not use theophylline if you are allergic to it or methylxanthines.
Theophylline does not work immediately; Do not use it to relieve sudden breathing problems like asthma or bronchospasm attack. Use a fast-acting inhalation medication if sudden shortness of breath occurs.
To make sure theophylline is safe for you, let your doctor know of your full medical history; if you have or had peptic ulcers, liver or kidney diseases, heart disease or any recurrent chronic condition, history of alcoholism or smoking, seizures, just to mention a few.
Your doctor might also need to know about your lifestyle habits like smoking, which decreases blood levels of theophylline and might affect its effectiveness.
Starting or stopping smoking changes the way your body uses theophylline, and you may need to use a different dose. Your doctor may need to monitor your blood levels more closely to determine if you need a dose adjustment.
Older people and children may be more sensitive to the side effects of theophylline. Careful monitoring of side effects and drug blood levels is recommended.
Theophylline can affect the results of certain medical tests. Tell any doctor who treats you that you are using theophylline before medical tests.
If you miss a dose, skip the missed dose and take your next dose at the regular time. Do not double the dose to catch up.
This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Always take note to tell your doctor about your medical history, especially of allergic reactions and existing conditions before you start taking theophylline.
The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.