Please read this if your GP has recommended this treatment, you need to understand and know what I am going to tell you.
I've been on this, or I was on this, for about two years. I was also using Benzoyl Peroxide and used Erythromycin (another antibiotic), to treat acne.
Antibiotics, at best, kill about 50%-75% of your acne, they will never get rid of your acne as the cause, i.e. hormones, allergies, immune system, is not treated. No matter how much you kill the Propionibacterium acnes, they are naturally occurring on your skin (and perform other functions, like preventing more serious skin infections), and so will only keep coming back, and eventually after long term use (maybe two years or more) will become resistant to antibiotics.
MEANWHILE you are destroying your immune system, metabolism and almost everything in your body. The gut contains bacteria, and one of the main warned side affects of antibiotics are diarrhoea, wind, bloating i.e. impaired gut function. The antibiotics demolish the microflora in your gut, and this ecosystem is what controls your immune system, nutrition intake and metabolism. Please do feel free to google any of this, I'm am 100%, have consulted many doctors, read much research, these are FACTS, I will not delve into speculation here. There is plenty of that about on these kind of websites.
You either have two acne types as far as I am concerned, you will either grow out of it post-puberty, i.e 19-20 maybe 21. In which case you need to just DEAL with it. Acne is horrible, it ruins self esteem, it feels unfair that you have it, you wish you could be 'normal' like everyone else. But such a high percentage of teenagers suffer from acne, it is not actually such a dramatic thing, and in most cases your acne WILL be gone by your 20's.
a) This is the important bit:
HOWEVER, if you take antibiotics in your teenage years to try control your skin, you will not clear your skin fully (so you will not be satisfied, believe me I know, you want it all gone, even if there are 3 or 4 spots left, you'll still feel as bad as if there were 9-10. Or 20% back covered in acne, compared to 80%. Any or other similar ratios.) In the process you will have made yourself open to serious health issues in the future, I'm talking potentially many years of weak immune system, diarrhoea, nausea, allergies (milk, egg, wheat) and if you think living with acne is hard - you won't survive with this. This is a very real issue and problem, sure it may not happen to you, but what antibiotics do is they leave you open to stomach infections, and if you get one of those, they can last for years, or permanently alter your stomach function so you no longer can eat wheat, milk, or anything, without feeling severely ill!
OR b) you may have adult acne, in which case antibiotics will not make a difference, and you need to take something more considerable like accutane, which WILL cure you 100%, with possible side effects. This is far more preferable to antibiotics, which do not 100% cure you, and WILL cause side effects, and sometimes long term.
As for benzoyl peroxide, it may dry your skin, and leave you open to skin infections when you finish using it (damaged skin + not natural bacteria left to fight off infection) but all in all, acne IS a current issue, so I think benzoyls pro's weigh heavier than it's cons.
That's me done, I just had to leave this information here, even if its just to settle my mind that I have tried to help others. I used to browse this forum desperately searching for a 'cure', turns out my severe bacne and mild facial acne faded by themselves when I stopped benzoyl and left the teenage years. But now my intestinal dysbiosis lives with me, and I am having to pay £3000 pound for treatment, as well as live with the health consequences. In hindsight it is not worth the risk people, I hope I can get that point across to you.
Best of luck