Beclometasone/Formoterol (Fostair)
Is It Right for You?
A complete guide to Beclometasone/Formoterol (Fostair) — what it treats, how it works, dosages, side effects, and when a clinician may prescribe it following an online consultation.
What Is Beclometasone/Formoterol (Fostair)?
Fostair is a fixed-dose combination inhaler containing beclometasone dipropionate (an inhaled corticosteroid, ICS) and formoterol fumarate (a long-acting beta-2 agonist, LABA). It is available in two strengths: Fostair 100/6 micrograms and Fostair 200/6 micrograms per actuation, and is formulated as both a pressurised metered-dose inhaler (pMDI) and a dry powder inhaler (Fostair NEXThaler).
Fostair uses an extrafine aerosol particle technology, producing smaller aerosol particles than conventional pMDIs. This extrafine formulation enhances deposition of both the ICS and LABA throughout the entire bronchial tree — including the small airways — at lower absolute doses of beclometasone compared to coarser-particle formulations, potentially improving efficacy and reducing local oropharyngeal side effects.
Fostair is a prescription-only medication in the UK. A licensed clinician must assess your respiratory diagnosis, severity of disease, and inhaler technique before prescribing.
What Conditions Is Fostair Used For?
Fostair is used for :
maintenance therapy of asthma in patients not adequately controlled on inhaled corticosteroid monotherapy alone; Fostair 100/6 is also licensed as maintenance and reliever therapy (MART) in asthma
symptomatic maintenance treatment of COPD in adults (Fostair 100/6)
Fostair is prescribed for regular, daily preventative use. It does not provide rapid bronchodilation for the immediate relief of acute breathlessness or wheeze. A separate short-acting beta-2 agonist (SABA) rescue inhaler (such as salbutamol) must be available for acute symptom relief — except in the MART regimen where Fostair 100/6 also serves as the reliever.
How Does Fostair Work?
Fostair combines two drug classes with complementary mechanisms of action, each targeting different aspects of airway pathophysiology in asthma and COPD:
Beclometasone dipropionate (inhaled corticosteroid) — beclometasone suppresses airway inflammation by binding to glucocorticoid receptors in airway epithelial cells and immune cells, reducing the expression of pro-inflammatory cytokines (IL-4, IL-5, IL-13), decreasing eosinophil infiltration into the bronchial mucosa, reducing submucosal oedema, and inhibiting mucus hypersecretion. Regular ICS use reduces airway hyperresponsiveness, prevents symptom progression, and reduces the risk of severe exacerbations. Beclometasone dipropionate is converted to its active metabolite beclometasone-17-monopropionate (B-17-MP) within the lung.
Formoterol fumarate (long-acting beta-2 agonist) — formoterol binds to beta-2 adrenergic receptors on bronchial smooth muscle, activating adenylyl cyclase and increasing intracellular cyclic AMP. This relaxes airway smooth muscle, producing bronchodilation. Formoterol has both rapid onset (within one to three minutes) and long duration (approximately 12 hours) of action. It also reduces mast cell mediator release and improves mucociliary clearance.
Together, the ICS suppresses the underlying inflammatory process while the LABA maintains bronchial patency, resulting in better symptom control, improved lung function, and reduced exacerbation risk compared to either component used alone.
Dosages & Administration
The correct dose depends on the type and severity of infection, age, weight, and kidney function. Always follow your clinician's instructions. The table below is for general reference only.
Administration Tips
Use your Fostair inhaler every day as prescribed, even when feeling well. The benefits of ICS therapy — reduced inflammation and lower exacerbation risk — are only maintained with regular use.
For the pMDI: Shake the inhaler well before each use. Exhale fully, place the mouthpiece between lips, press the canister as you breathe in slowly and deeply, then hold your breath for ten seconds.
Use a spacer device with the pMDI if coordination is difficult. A spacer significantly improves drug delivery to the lungs and reduces oropharyngeal deposition.
Rinse your mouth with water and spit after each use. This is essential to reduce the risk of oral candidiasis (thrush) caused by local corticosteroid deposition.
For Fostair NEXThaler (dry powder): Do not shake. Load the dose by opening the cover, exhale away from the mouthpiece, inhale forcefully and deeply.
Carry a SABA rescue inhaler (unless using Fostair MART regimen) at all times for sudden onset of breathlessness or wheeze.
Side Effects of Fostair
Most side effects are mild and resolve on their own. Serious side effects are rare but require immediate medical attention.
- Oral candidiasis (oral thrush) — local corticosteroid deposition in the oropharynx; prevented by rinsing mouth after each use
- Dysphonia (hoarse voice) — common with ICS inhalers; mouth rinsing and spacer use reduce risk
- Headache
- Palpitations — due to formoterol's beta-2 agonist activity
- Tremor — beta-2 stimulation of skeletal muscle
- Throat irritation and cough
- Hypokalaemia — beta-2 agonists shift potassium intracellularly; usually mild
- Paradoxical bronchospasm — worsening wheeze and breathlessness immediately after inhalation; stop Fostair and use a rescue SABA; seek urgent medical attention
- Severe hypokalaemia — particularly at high doses or with concurrent diuretic use; muscle weakness, cramps, cardiac arrhythmia
- HPA axis suppression and adrenal insufficiency — with high doses of beclometasone over prolonged periods; risk of adrenal crisis during physiological stress; signs of adrenal insufficiency include lethargy, nausea, and hypotension
- Severe allergic reaction / anaphylaxis
- Cardiac arrhythmia — high-dose or excessive use of formoterol; palpitations, irregular heartbeat
If Fostair MART reliever use is increasing beyond two occasions per week, this indicates deteriorating asthma control and requires urgent clinical review. Over-reliance on reliever doses without medical reassessment risks a life-threatening acute attack. Fostair must never be used as the sole treatment for acute severe asthma.
Drug Interactions
Always disclose all prescription drugs, over-the-counter medicines, vitamins, and supplements to your clinician or pharmacist before starting Fostair.
beta-blockers antagonise the bronchodilatory effect of formoterol and can precipitate severe bronchospasm in asthmatic patients. Cardioselective beta-blockers should be used with extreme caution; non-selective beta-blockers are contraindicated.
formoterol can prolong the QT interval; additive risk of arrhythmia with other QT-prolonging agents.
additive hypokalaemic effect with beta-2 agonists; monitor serum potassium, particularly at high doses.
may potentiate cardiovascular effects of formoterol; use with caution.
Important Warnings
Fostair is a maintenance inhaler and must not be used as the only treatment for acute breathlessness. Patients (except those on the MART regimen) must always carry a separate SABA rescue inhaler. Failure to have rescue medication available in acute asthma can be life-threatening.
Beta-blockers — including topical ocular formulations — can block the bronchodilatory effect of formoterol and provoke severe, potentially fatal bronchospasm in asthmatic patients. Patients requiring a beta-blocker for cardiovascular reasons should be managed under specialist supervision.
High-dose inhaled corticosteroids can suppress the HPA axis. Patients transferring from oral corticosteroids to inhaled corticosteroids are at particular risk of adrenal crisis during physiological stress. Carry a steroid emergency card if applicable.
High doses of beta-2 agonists combined with diuretics, theophylline, or other hypokalaemic agents can cause dangerous serum potassium falls. Monitor electrolytes in patients at risk.
Speak to a Clinician About Treatment
Getting advice no longer means sitting in a waiting room. Through The GP Service, you can consult with a licensed clinician in minutes — from home, on your lunch break, or wherever works for you. If treatment is clinically appropriate, your clinician can issue a prescription during the consultation. A consultation does not guarantee a prescription.
The treatment you need, when you need it.
Fostair FAQs
Both contain the same beclometasone/formoterol combination at the same doses but use different inhaler devices. Fostair pMDI is a pressurised metered-dose inhaler requiring coordination of actuation and inhalation; a spacer is recommended. Fostair NEXThaler is a breath-actuated dry powder inhaler requiring a forceful inhalation manoeuvre. Your clinician will prescribe the device best suited to your technique and preference.
Beclometasone is a corticosteroid; residual drug deposited in the oropharynx can suppress local immune defences and promote overgrowth of Candida albicans, causing oral thrush (white patches and soreness in the mouth). Rinsing thoroughly with water and spitting after every use significantly reduces this risk.
MART stands for Maintenance and Reliever Therapy. In the MART regimen, Fostair 100/6 is used both as a regular twice-daily maintenance dose and as an as-needed reliever, replacing the need for a separate SABA inhaler. It is suitable for patients with moderate to severe asthma whose symptom control is suboptimal. MART use requires additional patient education and should only be initiated under clinician guidance.
Fostair (unless on the MART regimen) is not a rapid-relief inhaler and should not be the only treatment used in an acute asthma attack. Always use your separate SABA rescue inhaler (e.g. salbutamol) for acute symptoms. If symptoms do not improve promptly, call 999.
Patients taking high-dose inhaled corticosteroids — or who have recently stopped oral corticosteroids — may need to carry a Steroid Emergency Card advising healthcare professionals of the potential for adrenal suppression. Your clinician will advise whether a steroid card is appropriate for you.