Although an epi-pen-like device is the correct treatment for anaphylaxis, if the patient's airway is becoming obstructed, and adrenaline is not available (or has already been expended), several puffs (some sources say 8-10) from an asthma inhaler intended for treating an acute asthma attack, particularly one containing salbutamol (also known as albuterol), can provide some relief. Ideally, it should be delivered through a spacer.
In my experience, more people carry asthma inhalers than epi-pens. However, this should only be done when the patient's airway is swelling and potentially becoming obstructed (they will have a wheeze or difficulty moving air). In this case, the consequences of doing nothing may include the patient dying. Giving a drug to a patient who doesn't usually take it is not a good idea, and youas there's a risk of adverse reaction from the drug itself. Salbutamol also increases the heart rate. You should still seek emergency help.
Salbutamol is a bronchodilator, and will dilate the airways in the lungs, but will not help to relieve an upper airway obstruction.