Theophylline opens the airways and is used in asthma and COPD. In South Africa it appears mostly inside combination cough and chest syrups. It is an older medicine with a narrow safety margin — the dose that works and the dose that harms are closer together than with almost anything else in a pharmacy.

What is Theophylline?

Theophylline is a methylxanthine, chemically related to caffeine. The South African Medicine Price Registry lists it mainly as a component of combination syrups, mostly Schedule 1 and 2:

Product	Form	Contains theophylline with
Alcophyllin	Syrup	Theophylline (with anhydrous theophylline)
Alcophyllex	Syrup	Diphenhydramine, ammonium chloride, sodium citrate
Theophen	Syrup	Etofylline nicotinate
Theophen Compound Elixir	Syrup	Ammonium chloride, diphenylpyraline
Dynalex, Actophlem	Syrup	Ammonium chloride, diphenylpyraline, etofylline
Diatussin / Biotussin	Syrup	Ammonium chloride, diphenhydramine, menthol

Note what most of these have in common: theophylline is not the only active ingredient. Most also contain a sedating antihistamine and an expectorant, so the cautions of those apply too.

Theophylline works in two ways. It relaxes the smooth muscle in the airways, widening them; and at lower concentrations it has an anti-inflammatory effect on the airway lining. It also stimulates the diaphragm and the respiratory drive.

The defining feature of theophylline is its narrow therapeutic index. The blood level needed for benefit sits close to the level that causes toxicity, and many ordinary things shift it — a chest infection, a fever, stopping smoking, starting an antibiotic. This is why theophylline has largely been displaced by inhaled treatments, which deliver medicine to the airways directly with a fraction of the body-wide exposure.

What is Theophylline commonly used for?

Asthma, as an add-on where inhaled treatment is not enough.
COPD (chronic obstructive pulmonary disease), similarly.
Chronic bronchitis and wheezy chest symptoms, which is what most of the South African combination syrups are sold for.
Cough with chest tightness, in those combination products.
Reversible airway obstruction generally.
Apnoea of prematurity, in neonatal units — a specialist hospital use.

Two things need saying clearly.

It is not a reliever. If you are wheezing or short of breath now, use your reliever inhaler. Theophylline is a background treatment and does not replace emergency asthma treatment.

It is not first-line. Modern asthma and COPD care is built on inhalers — an inhaled steroid for control, a bronchodilator for symptoms. Those deliver treatment directly to the airways with far fewer side effects. Theophylline sits behind them, and if you are relying on a theophylline syrup for asthma symptoms rather than on inhalers, that is worth a conversation with a doctor.

Asthma that needs regular treatment needs a proper assessment, not a cough syrup from the shelf. Poorly controlled asthma kills people, and it is highly treatable.

How Theophylline fits into this medicine category

Group	Examples	Role
Methylxanthines	Theophylline, aminophylline	Older oral bronchodilator; narrow safety margin
Inhaled steroids	Budesonide, fluticasone	The mainstay of asthma control
Reliever inhalers	Salbutamol	Acute symptoms — the emergency treatment
Long-acting bronchodilators	Formoterol, salmeterol, tiotropium	Maintenance in asthma and COPD
Leukotriene blockers	Montelukast	Asthma with allergic rhinitis
Antihistamines	Cetirizine (Austell Cetirizine), chlorphenamine (Rhineton)	Allergy, not airway obstruction

See the allergy, cold and flu medicines hub.

What to check before using Theophylline

Tell every prescriber that you take theophylline, because the list of things that change its blood level is unusually long.

Raise theophylline levels (risk of toxicity): ciprofloxacin, erythromycin and clarithromycin, fluconazole, allopurinol, cimetidine, verapamil, diltiazem, some antidepressants, the oral contraceptive pill — and fever, viral infections, heart failure and liver disease.

Lower theophylline levels (loss of effect): carbamazepine, phenytoin, phenobarbital, rifampicin, St John’s wort — and smoking.

That last one causes real trouble. Smoking speeds up theophylline breakdown, so smokers need higher doses. Stopping smoking can push a stable dose into the toxic range within days. If you stop smoking — or start — tell your doctor.

Also tell your doctor if you:

Have a heart rhythm problem, heart failure, liver disease, an overactive thyroid, epilepsy, or a stomach ulcer.
Are elderly, where clearance is slower.
Are pregnant or breastfeeding.
Are treating a child — theophylline is cleared differently in children, and the combination syrups also contain sedating antihistamines.

Practical points:

Keep your blood tests if levels are being monitored.
Limit caffeine. Coffee, tea, cola and energy drinks add to the same effects.
Take it consistently, at the same times, and do not double up on a missed dose.
Do not switch brands or formulations without advice — modified-release products are not interchangeable.
Measure syrups with the device supplied.

Possible cautions and when to ask a pharmacist or doctor

Even at therapeutic levels, theophylline commonly causes nausea, stomach upset, headache, restlessness, difficulty sleeping, tremor and palpitations — much like too much coffee, for the same underlying reason.

Learn the signs of toxicity, because they escalate. Early: persistent nausea and vomiting, worsening tremor, agitation, insomnia, a racing heart. Later, and dangerously: confusion, a very fast or irregular heartbeat, and seizures.

Seizures and arrhythmias can occur without much warning, and theophylline toxicity is a medical emergency.

Get emergency help for:

Persistent vomiting, especially with agitation or tremor.
A very fast or irregular heartbeat, or palpitations with dizziness or fainting.
Seizures, confusion or severe agitation.
Severe breathlessness or wheeze that your reliever does not settle — treat this as an asthma attack.
Swelling of the face, lips or tongue, or difficulty breathing.

Contact your doctor if:

You develop a fever or chest infection, or are started on a new antibiotic — both can raise theophylline levels.
You stop or start smoking.
Asthma symptoms are increasing, you are using your reliever more often, or you are waking at night with symptoms.
You feel jittery, sleepless or nauseated on it.
You are using a chest syrup regularly rather than occasionally — that suggests a condition needing proper treatment.

Related medicine guides

Frequently asked questions

What is theophylline used for? Opening the airways in asthma and COPD, and relieving chest tightness and wheezy cough. In South Africa it appears mostly inside combination chest syrups.

Is it a cough medicine? It is a bronchodilator that appears in cough and chest syrups, usually alongside an antihistamine and an expectorant. It does not suppress cough directly.

Can I use it during an asthma attack? No. Use your reliever inhaler. Theophylline is a background treatment.

Why does it make me jittery? It is chemically related to caffeine and has similar effects — restlessness, tremor, palpitations and poor sleep.

Why does smoking matter? Smoking speeds up its breakdown, so smokers need more. Stopping smoking can push a stable dose into the toxic range within days — tell your doctor.

Can I take antibiotics with it? Tell your doctor. Ciprofloxacin, erythromycin and clarithromycin all raise theophylline levels significantly.

Should I avoid coffee? Limit it. Caffeine adds to the same side effects.

Is it still commonly used? Less than it once was. Inhaled treatments have largely replaced it because they work directly on the airways with far fewer side effects.

What Is Theophylline Used For?