Current asthma medicines include inhalers. A common inhaler used in asthma is called a beta-agonist (for example salbutamol). They improve asthma symptoms by stimulating areas in the human airway resulting in widening of the human airway. Although these drugs are useful after the first dose, longterm use can cause worsening asthma symptoms.

Beta-blockers are the complete opposite type of medication. Just now they are avoided in patients with asthma as after the first dose they can cause airway narrowing and cause an asthma attack.

New research has suggested that long term use of beta-blockers can reduce airway inflammation which can improve asthma control and improve symptoms.

This research was done in asthmatic patients who didn't need inhaled steroids to control their asthma. What the investigators want to do is see if the same benefit of beta-blocker use is asthma can be seen in people who take inhaled steroids.

Inclusion Criteria:

• Male and female volunteers with stable mild intermittent or mild persistent asthma.
• Stable defined as: FEV1 (Forced Expiratory Volume in 1second) >80% predicted with diurnal FEV1 variation <30% when LABA (Long Acting Beta Agonist) washed out.
• Methacholine PC20 <4mg/ml.
• Ability to perform spirometry, IOS (Impulse Oscillometry), bronchial challenge and all domiciliary measurements.
• Ability to obtain Informed consent.
• Mild to Moderate Asthmatics taking ≤1000μg BDP (Beclomethasone Diproprionate) per day or equivalent.
• Withhold LABAs for 1 week prior to study.

Exclusion Criteria:

• Uncontrolled symptoms of asthma.
• Resting BP (Blood Pressure) <110 systolic or HR (Heart Rate)<60.
• Pregnancy or lactation.
• Known or suspected sensitivity to the IMP (Investigational Medicinal Product)(s).
• Inability to comply with protocol.
• Any degree of heart block.
• Rate limiting medication including β blockers, rate limiting Calcium - Channel Blockers and Amiodarone.
• Any other clinically significant medical condition that may either endanger the health or safety of the participant, or jeopardise the protocol.
• An asthma exacerbation within the last 6 months.