Salbutamol inhaler: uses, side effects and cautions

Salbutamol belongs to the group of medicines called bronchodilators. In the UK it is prescribed to relieve the coughing, wheezing, chest tightness and breathlessness of asthma and chronic obstructive pulmonary disease (COPD). Because it acts quickly it is called a reliever, as distinct from the daily preventer inhaler that most people with these conditions are also given.

It is supplied mostly as a hand-held inhaler, and in more severe disease it can also be given through a nebuliser, a machine that turns liquid medicine into a mist breathed through a mask or mouthpiece. Nebulised treatment is usually kept for severe asthma or COPD and for hospital use, although some people are loaned a home nebuliser.

During an asthma flare or a COPD exacerbation the bands of muscle around the small airways tighten and the tubes narrow. Salbutamol relaxes those muscles, so the airways open and air moves more easily. It does not treat the underlying inflammation, which is why it is a rescue treatment and not a substitute for preventer therapy.

The NHS describes a noticeable improvement within a few minutes of a dose, with the effect lasting for roughly 4 to 6 hours. Salbutamol and terbutaline are the two main reliever bronchodilators; the NHS says they work equally well, so a switch to terbutaline may be considered when someone struggles with the salbutamol device.

Most adults and children of any age can use a salbutamol inhaler. Nebulised salbutamol in under-18s is only used on specialist advice, because a child who needs a nebuliser at home should be followed by a specialist team.

The NHS lists conditions where a prescriber should be told before salbutamol is started because extra care may be needed:

• a previous allergic reaction to salbutamol or any other medicine

• any heart problem

• an overactive thyroid

• low blood potassium

• diabetes

The NHS says the usual use for adults and children is 1 or 2 puffs when needed, up to a maximum of 4 times in 24 hours. The same 1 or 2 puffs may be taken before a known trigger such as exercise or contact with an animal. Your own instructions from your prescriber and the patient leaflet for your particular device take priority over any general description.

Technique matters because a poorly used inhaler delivers very little drug to the lungs. Pressurised metered-dose inhalers (the traditional puffer) may be paired with a spacer, a large plastic or metal chamber that is especially useful for young children. Dry-powder devices need a different, quick and deep breath. Remove the mouthpiece cover fully before use, shake a pressurised inhaler 4 or 5 times to clear loose objects, and replace the cover afterwards. Ask a pharmacist, nurse or doctor to watch you if your technique has not been checked within the last year.

The NHS describes salbutamol as having very few side effects when used as directed. More than 1 in 100 people notice feeling shaky, a faster heartbeat that settles quickly, or a headache. Shakiness often eases if one puff is enough rather than two, and these effects tend to lessen as the body adjusts.

Rarer problems need prompt advice. Muscle pain, weakness or cramps, or an irregular or more noticeable heartbeat can point to low potassium. A fast irregular heartbeat that does not settle, or severe dizziness, also warrants contact with a doctor or NHS 111. New or worsening breathlessness or chest pain after a dose means calling 999 or going to A&E.

A serious allergic reaction is rare, but swelling of the lips, mouth, throat or tongue, struggling to breathe, a tight throat, blue, grey or pale skin or lips, sudden confusion or drowsiness, or collapse all need a 999 call. Do not drive yourself to hospital. Suspected side effects can be reported through the Yellow Card scheme.

In a sudden asthma attack the NHS says the inhaler can be used more heavily, up to 10 puffs, with 30 to 60 seconds between puffs and a shake each time. Call 999 if there is no improvement after 10 puffs or if you feel worse at any point. If symptoms are no better after 10 minutes and no ambulance has arrived, the NHS says to repeat the puffs, one every 30 to 60 seconds up to a maximum of 10.

Taking more than the advised amount commonly causes a pounding or fast heartbeat and shakiness. Chest pain after taking too much needs 999; palpitations after an excess dose call for NHS 111 advice. Bring the packet and any remaining medicine if you attend A&E.

The NHS says it is fine to use salbutamol during pregnancy and breastfeeding, and that untreated asthma is a greater concern than the inhaler. It also reports no evidence of an effect on fertility and no effect on contraception, including the combined pill and emergency contraception.

Several medicines can lower blood potassium when combined with salbutamol: water tablets such as bendroflumethiazide or furosemide, steroids such as prednisolone, and the other breathing treatments theophylline and aminophylline. Beta blockers such as bisoprolol can blunt salbutamol, so the prescriber weighs the pros and cons of using both. Medicines for depression are also flagged. Alcohol and food are not restricted. If salbutamol makes you dizzy or shaky, do not drive, cycle or use tools until it passes. The NHS has not tested herbal remedies with salbutamol, so tell your pharmacist about any you take.

The NHS suggests a simple diary of how often the inhaler is needed. It helps you and your clinician judge control, and it shows when to order a replacement, because some inhalers hold a fixed 200 doses and it is not always obvious that they are nearly empty.

Most people use salbutamol for years. Frequency of use may fall as breathing improves, but the NHS advises always carrying one, and not stopping unless a doctor says so. Pressurised inhalers use propellants that are potent greenhouse gases, whereas dry-powder devices do not, so a clinician may discuss a lower-carbon device if it is safe for you and you can use it properly.