Theo-24 Sr (Theophylline) — Patient Information (Australia)
Theo-24 Sr is a long-acting (sustained-release) medicine containing theophylline. It is used to help improve breathing in people with certain long-term lung conditions. This guide explains how Theo-24 Sr works, how it is used, common timing tips, interactions (including with food, alcohol and other medicines), safety considerations, and frequently asked questions for Australia.
Basic product information
- Active ingredient: Theophylline
- Brand name: Theo-24 Sr
- Formulation: Sustained-release (Sr)
- Common strengths: Available in multiple strengths depending on local supply (your pharmacist can confirm the exact strength you have).
- Medicinal class: Xanthine; bronchodilator and anti-inflammatory-related effects
- Typical dosing frequency: Usually once daily due to sustained-release design
What Theo-24 Sr is used for
Theophylline is used as a controller/reliever-supporting bronchodilator in selected patients with chronic breathing conditions. In practice, it may be considered when symptoms are not fully controlled with first-line treatments, or when additional bronchodilation is needed.
Indications (general uses)
- Asthma: In some patients as add-on long-term therapy.
- Chronic obstructive pulmonary disease (COPD): For selected patients with chronic airflow limitation where additional bronchodilation may help.
Your healthcare professional will determine whether Theo-24 Sr is suitable for you based on your lung condition, current treatments, and risk factors for side effects.
How Theo-24 Sr works (mechanism of action)
Theophylline helps open airways and can reduce some inflammation-related processes in the lungs. It primarily works by:
- Relaxing airway smooth muscle (bronchodilation), improving airflow.
- Modulating inflammatory pathways and cellular signalling (which may contribute to symptom control in some people).
- Enhancing diaphragmatic and respiratory muscle function in some cases.
- Reducing bronchoconstriction tendency in the airways.
Because the medicine is sustained-release, it aims to provide steadier theophylline levels over the day compared with immediate-release forms. However, theophylline has a relatively narrow margin between benefit and toxicity, so careful dosing and interaction management are important.
Pharmacokinetics: how your body handles the medicine
Understanding pharmacokinetics (what the body does to the medicine) can help explain why timing, consistency, and interaction checks matter.
Key points (typical behaviour)
- Absorption: Theo-24 Sr releases theophylline gradually to maintain therapeutic levels.
- Onset: Some bronchodilation benefit may occur within hours; full steady effect is usually assessed over days as levels stabilise.
- Distribution: Theophylline distributes widely in the body.
- Metabolism: Mainly metabolised in the liver by enzymes that can be affected by many drugs and smoking status.
- Elimination: Excretion is primarily via kidneys and the metabolite pathway.
Therapeutic drug monitoring may be used in some patients because theophylline levels can vary. This can be especially relevant when you start therapy, change dose, or begin interacting medicines.
Typical use and timing
Theo-24 Sr is commonly prescribed because it is sustained-release. Consistent timing helps maintain more stable blood levels.
When to take it
- Take at the same time each day.
- Swallow whole. Do not crush or chew the sustained-release preparation.
- Follow your dosing schedule. Changing the timing or missed doses can affect blood levels.
Missed dose guidance (general)
If you miss a dose, take it when you remember unless it is close to your next dose. If you are unsure, ask your pharmacist for advice. Do not double the dose to make up for a missed tablet/capsule.
Food interactions
Food can influence how quickly theophylline is absorbed, and some foods may alter theophylline metabolism indirectly. Consistency is the key.
Alcohol and smoking notes related to food
- Alcohol can increase the risk of side effects in some people and may affect metabolism.
- Smoking can affect theophylline breakdown; starting or stopping smoking may change how the medicine behaves.
General food advice
- Maintain a consistent routine: take Theo-24 Sr the same way with respect to meals (for example, always with food or always on an empty stomach) if your clinician has advised a specific approach.
- Be cautious with grapefruit/grapefruit juice: some products can influence metabolism; ask your pharmacist if you regularly consume them.
- Avoid sudden dietary changes that affect liver enzyme activity (for example, starting supplements that strongly influence metabolism).
Alcohol interactions
Theophylline can cause side effects such as headache, nausea, and tremor. Alcohol may increase these effects or contribute to dehydration and stomach irritation. For safety, it is generally recommended to limit alcohol and seek advice if you plan to drink.
If you experience palpitations, vomiting, severe headache, dizziness, or worsening tremor after drinking alcohol while using theophylline, seek medical advice promptly.
Medicine interactions (important)
Many medicines can increase or decrease theophylline levels by affecting liver enzymes or absorption. Some interactions can raise the risk of toxicity, while others can reduce effectiveness.
Medicines that may increase theophylline levels (higher toxicity risk)
- Some antibiotics (e.g., macrolides such as clarithromycin; quinolones such as ciprofloxacin—varies by product and patient factors)
- Certain antifungal medicines
- Cimetidine and some other ulcer/acid-reducing medicines
- Some heart rhythm or other cardiovascular medicines
- Oral contraceptives (in some cases)
Medicines that may decrease theophylline levels (reduced effect)
- Antiseizure medicines that induce liver enzymes (e.g., phenytoin, carbamazepine, phenobarbital)
- Rifampicin (TB treatment)
- Smoking changes (starting/stopping)
- Some herbal products that induce enzymes (for example, St John’s Wort)
Other interaction considerations
- Caffeine (coffee, tea, cola, energy drinks) may increase the chance of side effects like jitteriness and palpitations.
- Sympathomimetics/bronchodilators used for rescue relief may add to heart-rate effects in some people.
- Medicines affecting potassium (or other electrolyte balance) may be relevant in severe cases, especially during toxicity.
Always tell your pharmacist and healthcare professional about all medicines you take, including over-the-counter products, herbal supplements, and nicotine products. If a new medicine is started, you may need closer monitoring.
Dosing: how Theo-24 Sr is commonly taken
Dosing of theophylline must be individualised. Factors include age, liver function, other medicines, smoking status, and baseline risk of side effects. Due to the narrow therapeutic window, your healthcare professional may start at a lower dose and adjust.
General dosing principles
- Start low and adjust carefully: dose changes may be made gradually.
- Once-daily administration is typical for sustained-release formulations.
- Therapeutic drug monitoring may guide dosing in some patients, especially when interactions exist or symptoms change.
- Do not self-adjust: never increase dose to “catch up” missed doses.
Example dosing schedule (illustrative)
The exact dose and strength you should use are determined by your clinician. The table below provides an illustrative overview of how sustained-release theophylline is often scheduled (not a substitute for your prescription instructions).
| Patient situation | Typical approach | Why it matters |
|---|---|---|
| New start | Low starting dose; then adjust based on response and tolerance | Minimises risk of early side effects |
| Already stable | Maintain consistent once-daily schedule | Supports steadier blood levels |
| Drug changes or interactions | Possible dose review and closer monitoring | Other medicines can raise or lower theophylline levels |
| Older age or liver impairment | Often lower doses and closer monitoring | Liver metabolism may be reduced |
| Smoking changes | Reassess dose if you start or stop smoking | Smoking status can affect enzyme activity |
Safety profile: side effects and what to watch for
Theophylline can cause side effects, particularly if levels become too high or if you are sensitive to the medicine. Many people experience mild effects early, while others may have no problems at all.
Common side effects
- Nausea, stomach discomfort
- Headache
- Tremor or feeling “jittery”
- Restlessness or insomnia
- Increased heart rate/palpitations (sometimes)
Serious signs of toxicity (seek urgent medical advice)
Theophylline toxicity can be dangerous. Contact emergency services or seek urgent medical help if you experience symptoms such as:
- Persistent vomiting
- Severe tremor or agitation/confusion
- Fast, irregular heartbeat or chest pain
- Seizures
- Severe worsening of breathing (especially if accompanied by fast heartbeat or dizziness)
Risk factors for side effects
- High caffeine intake (coffee, tea, cola, energy drinks)
- Interacting medicines that raise theophylline levels
- Liver impairment or advanced age
- Viral illness or sudden changes in health status
- Starting or stopping smoking
- Not taking the medicine consistently (timing/dose changes)
Practical use tips (to get the best results safely)
- Keep timing consistent: take at the same time each day.
- Don’t crush or chew: sustained-release forms must be swallowed whole.
- Avoid “hidden caffeine”: be cautious with energy drinks and some pre-workout supplements.
- Tell your pharmacist about all products: including herbal supplements and non-prescription cold/flu remedies.
- Monitor symptoms: note changes in breathlessness, wheeze, and rescue inhaler use.
- Watch for palpitations or tremor: report new or worsening symptoms promptly.
- Use a symptom action plan for asthma/COPD: ensure you know when to escalate care.
- Transport safely: keep tablets/capsules in the original pack and store as instructed on the label.
When to seek medical advice
Speak with your healthcare professional promptly if you:
- Have worsening breathing despite treatment
- Develop significant side effects (especially vomiting, marked tremor, palpitations, dizziness)
- Start a new medicine (including antibiotics or antifungals)
- Plan to change smoking habits
- Have symptoms of illness that might affect metabolism (e.g., fever, severe infection)
Alternative treatment options
Treatment for asthma and COPD typically includes inhaled medicines as first-line options. The best alternative to Theo-24 Sr depends on your diagnosis, severity, and current regimen.
Asthma alternatives (examples)
- Inhaled corticosteroids (ICS) for inflammation control
- ICS/LABA combination inhalers for symptom prevention
- Lung-targeted bronchodilators (e.g., long-acting beta agonists where appropriate)
- Biologic therapies for certain severe asthma phenotypes
COPD alternatives (examples)
- Long-acting bronchodilators (LAMA and/or LABA inhalers)
- Inhaled corticosteroids in selected patients
- Smoking cessation support and pulmonary rehabilitation
- Other add-on medicines based on exacerbation history
Theophylline may still be used in selected circumstances, but many patients are managed using inhaled controller strategies that have fewer systemic side effects than oral theophylline. Discuss your options with your clinician if you are experiencing side effects or inadequate control.
Market and legal context for Australia
In Australia, access to medicines is governed by the Australian regulatory framework and TGA (Therapeutic Goods Administration) requirements. Medicine availability, scheduling, and prescribing requirements can vary by product and formulation.
On an online pharmacy in Australia, customers typically receive appropriate guidance on safe use and may be asked for details relevant to suitability and safety. Availability may vary due to supply, regional distribution, and current medicine listing status.
Recent guidance and clinical practice considerations (high-level)
Australian asthma and COPD management typically emphasises stepwise care using inhaled medicines, with theophylline generally considered an option for selected patients. Because theophylline can interact with many medications and can cause systemic side effects, clinicians often weigh:
- Current inhaler regimen effectiveness
- Potential drug–drug interactions
- Patient risk factors (age, liver function, caffeine intake, smoking status)
- Whether therapeutic drug monitoring is needed
Always follow up if symptoms change, and do not start or stop interacting medicines without advice.
Delivery and availability (Australia)
Online pharmacy orders in Australia are commonly delivered by reputable courier services. Delivery times vary depending on your location (metro vs regional), stock availability, and courier schedules. When Theo-24 Sr is in limited supply, dispatch may be slightly delayed—your pharmacy listing will usually indicate current availability.
- Stock status: “In stock” or “Out of stock” indicators (if provided)
- Delivery estimate: shown at checkout where applicable
- Tracking: may be provided once dispatched
- Storage on arrival: keep in a cool, dry place away from moisture and heat unless otherwise instructed
Frequently Asked Questions (FAQ)
1) How quickly will Theo-24 Sr work?
Some improvement may be noticed within hours, but steadier control is often assessed over several days as blood levels settle. If your symptoms are not improving, contact your pharmacist or healthcare professional rather than adjusting the dose yourself.
2) Can I take Theo-24 Sr with food?
Many people take it with or without food depending on tolerability. What matters most is consistency and following the specific advice given to you. If you experience nausea or stomach upset, ask whether taking with food might help.
3) Can I drink coffee or other caffeinated drinks?
It’s best to limit caffeine (coffee, tea, cola, energy drinks) because caffeine can increase the risk of side effects such as jitteriness and palpitations while on theophylline. Keep caffeine intake consistent and ask your pharmacist if you’re unsure.
4) What should I do if I miss a dose?
Take it when you remember unless it’s close to the time for your next dose. Do not take an extra dose to “catch up.” If you’re uncertain, seek advice from your pharmacist.
5) Why do interactions matter so much for theophylline?
Theophylline is metabolised in the liver and can be affected by many medicines and lifestyle factors. Some interactions raise theophylline levels (increasing toxicity risk), while others reduce levels (reducing effectiveness). Because of this, clinicians may recommend monitoring and dose adjustments.
6) Do I need blood tests while taking Theo-24 Sr?
Some patients may benefit from theophylline blood level monitoring, particularly when starting therapy, changing dose, starting/stopping interacting medicines, or when side effects occur. Your clinician will advise if and when monitoring is needed.
7) Can I start or stop smoking while on Theo-24 Sr?
Smoking can change how the body clears theophylline. If you plan to quit or restart smoking, speak with your pharmacist or clinician—your dose may need review.
8) What are the warning signs of too much theophylline?
Seek urgent medical attention if you develop severe vomiting, persistent tremor, confusion, seizures, severe palpitations, or other serious symptoms. Mild side effects should also be reported, especially if they worsen.
9) Are there safer alternatives if I can’t tolerate theophylline?
Often, yes. Many patients use inhaled controller therapies and other bronchodilators that target the lungs with fewer systemic side effects. Discuss your situation with a healthcare professional to choose the best option for your condition.
10) How should I store Theo-24 Sr?
Store the medicine according to the instructions on the pack (typically at room temperature, protected from moisture and heat). Keep it out of reach of children.
Summary
Theo-24 Sr (theophylline) is a sustained-release medicine used in selected patients to improve breathing in asthma and COPD. It works by bronchodilating the airways and influencing related lung processes. Because theophylline can interact with many medicines and may cause significant side effects if levels rise, consistent dosing and careful interaction checks are essential. If you experience concerning symptoms—especially palpitations, persistent vomiting, severe tremor, or confusion—seek urgent medical advice.
