Theo-24 Sr (Theophylline) – Patient Information (Australia)

Theo-24 Sr contains theophylline in a slow-release (sustained-release) form. It is used to help open the airways and reduce breathing symptoms in certain lung conditions. This page explains how Theo-24 Sr works, how it’s taken, important safety considerations, and practical tips to help you use it safely.

Important: Always follow the instructions provided by your healthcare professional. Theophylline levels can be affected by other medicines, smoking, diet, and liver health. If you have questions about your specific dose or monitoring, speak with your pharmacist or doctor.

Basic product information

What is theophylline?

Theophylline is a medicine used as a bronchodilator (it helps relax airway muscles) and a mild anti-inflammatory agent in the lungs. In many countries, theophylline is used when other controller medicines are insufficient or not suitable.

Mechanism of action (how it works)

Theophylline works through multiple mechanisms, which can include:

• Relaxing smooth muscle in the airways (bronchodilation), helping reduce bronchospasm.
• Improving airflow by reducing airway constriction and increasing breathing efficiency.
• Modulating inflammatory pathways, which may contribute to improved long-term control.
• Influencing cellular signalling (including effects on cyclic nucleotide pathways), helping stabilise airway responses.

Typical use in respiratory conditions

Theo-24 Sr is commonly used as a maintenance medicine for conditions such as:

• Asthma (particularly for patients who need additional long-term control)
• Chronic obstructive pulmonary disease (COPD) (for symptom relief and maintenance in selected patients)

It is important to note that Theo-24 Sr is generally not intended to relieve sudden breathing attacks. For sudden symptoms, your healthcare professional may recommend a fast-acting “reliever” inhaler.

Indications (when it may be used)

In clinical practice in Australia, Theo-24 Sr may be considered when long-term control of symptoms is required and bronchodilation and symptom improvement are needed, particularly where other treatment plans are inadequate.

Your prescriber will determine suitability based on your symptoms, other medications, medical history (including liver function), and the risk of side effects.

How Theo-24 Sr is taken: timing and routine

Theo-24 Sr is a slow-release medicine designed to release theophylline over time. Keeping a consistent daily routine helps maintain steadier drug levels.

When to take it

• Usually once daily for SR products (confirm your exact schedule).
• Try to take your dose at a similar time each day.
• Many people take it in the evening to match sustained release coverage during the night, but your regimen may differ—follow your prescriber’s instructions.

With food or without food

Theo-24 Sr can be taken with or without food, but consistent habits matter. Your pharmacist or prescriber may advise based on how you respond and your tolerance.

How to swallow

• Swallow the capsule/tablet whole with water.
• Do not crush, open, or chew sustained-release forms unless instructed by your healthcare professional.
• If you miss a dose, take it when you remember unless it is close to the next dose—don’t double up. If unsure, ask your pharmacist.

Dosing: what you need to know

Theophylline dosing is individual and may require adjustment. Factors include age, body weight, smoking status, other medicines, and liver function. In some patients, a blood test for theophylline levels (“therapeutic drug monitoring”) may be recommended to reduce the risk of toxicity.

General dosing principles (patient-friendly)

• Doses are often started low and increased gradually if needed.
• The goal is symptom control while keeping the medicine within a safe therapeutic range.
• Your prescriber may review your response and side effects, and may check levels when risk is higher.

Example schedule (illustrative only)

Your exact dose may differ. Do not use the example below to decide your own dose.

• Often once daily due to SR formulation.
• Some patients may be prescribed different strengths to match their target dose.

Pharmacokinetics (how the body processes it)

“Pharmacokinetics” describes absorption, distribution, metabolism, and elimination. Understanding this helps explain why interactions are important.

Absorption

• With sustained-release formulations, theophylline is absorbed over a prolonged period.
• Peak levels typically occur hours after dosing, depending on the exact product and individual factors.

Distribution

• Theophylline distributes throughout body tissues, including the lungs.
• It may bind to proteins in the blood (which can be affected by illness and other medicines).

Metabolism

• Theophylline is mainly metabolised by the liver.
• Reduced liver function can increase theophylline levels and risk side effects.

Elimination

• Theophylline and its metabolites are eliminated from the body primarily via kidneys.
• Kidney impairment and age-related changes can affect elimination.

Because theophylline levels can vary significantly, medication changes should be discussed with a healthcare professional. This is especially important for antibiotics, antifungals, seizure medicines, and some cardiac medicines.

Food interactions

What you eat and drink can affect how much theophylline your body absorbs and how your level changes. To reduce variability:

• Keep your caffeine intake consistent. Coffee, tea, energy drinks, and some soft drinks contain caffeine that may add to side effects.
• Be cautious with alcohol (see the next section for more detail).
• If you are given dietary advice or start a new supplement, ask your pharmacist whether it could affect theophylline.

Alcohol interactions

Alcohol may increase the risk of side effects such as nausea, stomach upset, dizziness, and sleep disturbance. It can also influence liver metabolism and may alter drug handling in some people.

Practical advice:

• Avoid or limit alcohol while taking Theo-24 Sr, particularly when starting or changing your dose.
• If you drink alcohol, do so in moderation and discuss with your healthcare professional if you experience side effects.
• Seek advice promptly if you develop palpitations, severe headache, vomiting, or significant tremor.

Medicine interactions (very important for theophylline)

Theophylline interacts with many medicines. Some can increase theophylline levels (raising toxicity risk), while others can decrease levels (reducing effect). Always tell your pharmacist and doctor about all medicines you take, including over-the-counter products and herbal supplements.

Examples of medicines that may affect theophylline

This list is not complete, but common interaction categories include:

• Antibiotics (some types can increase theophylline levels)
• Antifungal medicines
• Medicines for seizures (some can reduce levels)
• Cardiac medicines (certain drugs can alter rhythm or metabolism)
• Some asthma/COPD medicines may add to side effects like tremor or heart rate changes
• Oral corticosteroids may influence metabolism or risk of side effects in some cases
• Herbal products (for example, St John’s wort) may affect levels

Smoking and vaping

Smoking can change theophylline metabolism. If you smoke, your prescriber may adjust your dose and monitor your response. If you stop smoking or start smoking, notify your healthcare professional promptly.

Safety profile: possible side effects

Like all medicines, Theo-24 Sr can cause side effects. Not everyone gets them. Side effects are more likely if theophylline levels are too high.

Common or mild side effects

• Nausea, vomiting, or stomach upset
• Headache
• Restlessness or trouble sleeping
• Tremor (shaking)
• Heartburn or indigestion

Serious side effects: get urgent medical help

Seek urgent medical assistance if you experience symptoms that may suggest toxicity, such as:

• Fast or irregular heartbeat, palpitations, chest discomfort
• Severe nausea or persistent vomiting
• Severe tremor, severe agitation, confusion
• Seizures
• Fainting or severe dizziness

Who needs extra caution?

Tell your prescriber if you have any of the following, as they may influence the risk-benefit balance and dosing:

• Liver disease or reduced liver function
• Heart rhythm problems
• History of seizures
• Recent severe illness, dehydration, or ongoing fever
• Older age
• Frequent changes in other medicines
• Significant alcohol use or high caffeine intake

Practical use tips for safer, more effective treatment

• Keep a consistent routine: take your dose at the same time each day and maintain consistent caffeine habits.
• Review your medication list whenever you start or stop any medicine, including antibiotics or antifungals.
• Do not change the dose without medical advice.
• Use an organiser or reminder if you have once-daily dosing.
• Be alert for early side effects (tremor, nausea, insomnia, palpitations) and contact your pharmacist/doctor if they appear.
• Discuss therapeutic drug monitoring if your doctor recommends blood tests. Monitoring can help maintain safe levels, especially if you have risk factors or interaction changes.
• Avoid crushing or altering SR tablets/capsules unless specifically instructed.

Timing considerations with other inhalers/respiratory medicines

Theo-24 Sr works as a maintenance bronchodilator, while reliever inhalers (like those containing salbutamol) are for sudden symptoms. Many patients use both kinds of treatment under a personalised asthma/COPD action plan.

Ask your pharmacist or healthcare professional how Theo-24 Sr fits into your broader respiratory plan, including when to use your reliever, controller inhalers, and any peak flow or symptom tracking.

Alternative options

Depending on your diagnosis (asthma vs COPD), severity, and previous response, alternatives may include:

• Inhaled corticosteroids (for asthma control, often used as part of combination inhalers)
• Long-acting beta₂-agonists (LABA) (often used in combination inhalers for asthma)
• Long-acting muscarinic antagonists (LAMA) (commonly for COPD)
• Short-acting reliever inhalers for acute symptoms
• Other oral medicines used for COPD/asthma under specific circumstances (your prescriber will tailor options to you).

Theophylline is generally selected when additional bronchodilation or specific treatment goals are needed. Do not switch medicines without guidance, as dosing schedules and monitoring requirements differ.

Australia: market and legal context

In Australia, the availability and dispensing requirements for medicines containing theophylline depend on current Therapeutic Goods Administration (TGA) scheduling and local prescribing/dispensing arrangements. Your pharmacist can confirm the exact requirements for Theo-24 Sr in your situation and ensure the medicine is sourced and supplied appropriately.

Medicines in this class may also require careful handling of interactions and monitoring due to the potential for toxicity at higher levels. Australian healthcare providers typically assess your risk factors and may recommend review after dose changes.

Recent guidance and monitoring considerations

Clinical guidance for asthma and COPD in Australia emphasises:

• Using evidence-based inhaled therapies as first-line maintenance where appropriate (especially for asthma).
• Individualising add-on therapy when symptoms are not controlled.
• Minimising risk by checking drug interactions and considering therapeutic drug monitoring for theophylline in higher-risk scenarios.
• Regular review of symptom control and medicine tolerability.

Because interaction profiles can change with new prescriptions or illnesses, it’s helpful to have your pharmacist perform a medication check whenever you start new treatments.

Delivery and availability (online pharmacy)

Availability can vary by supplier and strength of Theo-24 Sr. If your preferred strength is temporarily unavailable, we may offer:

• Alternative pack sizes or strengths where clinically appropriate
• Backorder or estimated restock dates (where possible)
• Advice on stock substitutions in line with pharmacy practice

Delivery times depend on your location in Australia and the courier service used. You’ll be shown estimated dispatch and delivery information at checkout. If there’s a delay, we’ll typically contact you (or send an email update) with the most current availability status.

Frequently Asked Questions (FAQ)

1) Is Theo-24 Sr the same as short-acting theophylline?

No. Theo-24 Sr is a sustained-release (SR) form designed to release theophylline gradually. Other theophylline products may have different release patterns and dosing schedules, so you should not substitute without advice.

2) How long does it take to work?

Some people notice symptom improvement within days, while full benefit may take longer depending on your condition and dose. If symptoms worsen or you’re using your reliever more often, contact your healthcare professional.

3) Can I take Theo-24 Sr with coffee or energy drinks?

It’s best to keep caffeine intake consistent and within a safe personal routine. Caffeine may increase side effects such as jitteriness, insomnia, or palpitations. If you need guidance, ask your pharmacist what caffeine amount is safest for you.

4) What should I do if I miss a dose?

If you miss a dose, take it when you remember unless it is close to the next scheduled dose. Don’t take a double dose to make up for the missed one. If you’re unsure, speak to your pharmacist.

5) Can I stop Theo-24 Sr suddenly?

Do not stop suddenly unless your prescriber instructs you to do so. Stopping may lead to loss of symptom control. Always discuss planned changes to your treatment.

6) Are blood tests required?

Some patients may need blood tests to check theophylline levels, especially if:

• there are drug interactions
• you have risk factors (e.g., liver issues, older age)
• symptoms suggest the level may be too high or too low
• your dose is being adjusted

Follow your healthcare professional’s plan for monitoring.

7) What side effects mean my dose may be too high?

Early warning signs can include nausea, vomiting, tremor, restlessness, insomnia, and palpitations. If symptoms are severe or you feel unwell, seek urgent medical help.

8) Can other medicines affect Theo-24 Sr even if they’re “just antibiotics”?

Yes. Many antibiotics and other medicines can change theophylline levels. Always check with your pharmacist before starting new medicines, including for short courses.

9) Is it safe for everyone with asthma or COPD?

Not necessarily. Theo-24 Sr may be unsuitable for some people depending on heart rhythm risk, seizure risk, liver function, and interaction potential. Your prescriber will weigh these factors and may choose other treatments if appropriate.

10) How should Theo-24 Sr be stored?

Store according to the instructions on the pack (typically at room temperature, away from moisture and heat). Keep medicines out of reach of children.

When to seek help urgently

Contact emergency services or seek urgent medical attention if you experience:

• Seizures
• Severe palpitations, fainting, or chest pain
• Persistent vomiting or inability to keep fluids down
• Confusion or severe agitation

Summary

Theo-24 Sr (theophylline sustained-release) helps improve airflow by relaxing airway muscles and supporting long-term symptom control. Because it can interact with many medicines and is processed primarily in the liver, safe use requires careful attention to timing, caffeine and alcohol habits, and medication changes. If you notice side effects—especially signs that could indicate high theophylline levels—seek advice promptly.