When treating patients of any age, you have to be very careful not to give them medication that would worsen their ailments. This is especially true for children and the elderly, as they have weakened immune systems and may not be able to fight off the effects of the medication.
For a ten year old child who has a history of asthma, the drug propranolol would be contraindicated. People with asthma have a very difficult time breathing due to restricted airways. The drug propranolol is used to constrict the lungs and would make it even harder for the patient to breathe.
Asthma, a disease involving increased resistance of the upper airways, is treated by administering drugs that produce bronchiolar dilation (i.e.,B2 agonists). B2 Agonists include isoproterenol, albuterol, epinephrine, and, to a lesser extent, norepinephrine. Antagonists, such as propranolol, are strictly contraindicated because they cause constriction of the bronchioles.