Advil is a brand name for ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and reduce fever. According to Drug Patent Watch [1], Advil's active ingredient is ibuprofen, which is widely used and considered safe for short-term use. However, the long-term effects of ibuprofen use in teenagers are not well understood.

One potential risk associated with the use of ibuprofen in teenagers is Reyes syndrome, a rare but potentially fatal condition that can occur in young people recovering from a viral infection. Reyes syndrome can cause liver and brain damage and is often associated with the use of aspirin or other salicylate-containing medications. According to the Mayo Clinic [2], the use of ibuprofen in teenagers with viral infections may increase the risk of Reyes syndrome. Therefore, it is recommended that teenagers avoid using ibuprofen if they have a viral infection or have recently recovered from one.

However, the Australian Drug Foundation [3] states that ibuprofen is generally safe for teenagers to use in the short-term to relieve pain and inflammation. The foundation recommends that teenagers should not exceed the recommended dose and should avoid taking ibuprofen on an empty stomach to reduce the risk of gastrointestinal side effects.

In conclusion, while ibuprofen is generally considered safe for short-term use, the long-term effects of ibuprofen use in teenagers are not well understood. Teenagers should avoid using ibuprofen if they have a viral infection or have recently recovered from one to reduce the risk of Reyes syndrome. It is also important for teenagers to follow the recommended dosage and avoid taking ibuprofen on an empty stomach to reduce the risk of gastrointestinal side effects.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.mayoclinic.org/diseases-conditions/reyes-syndrome/symptoms-causes/syc-20377255
[3] https://adf.org.au/drug-facts/ibuprofen/