Great advice from Isadora. I will also add something that I was told a by a number of travel doctors who have prescribed me Doxy - take it at the exact same time everyday, to the minute if you can. I would always take it at the same time everyday shortly after breakfast.
Thanks Dave! And, thanks for the "take at the same time daily" advice! I forgot to mention that. As with most medications (unless otherwise prescribed), all anti-malarials should be taken at the same time every day. If you forget one, take it as soon as you realize it, provided it is greater than 4 hours before your next pill. If you have forgetten for one full day, do NOT take two the next time just to catch up. Skip the forgotten one and continue the regimen. Taking a fogotten tablet less than 4 hours before the next one is due and then taking the regularly scheduled one will increase the chances of any nausea and can cause vomiting. It does not increase your protection.
Also, Doxy used long-term (and 7 months is considered long-term), some women may develop vaginal yeast infections as the Doxy can "kill off" the naturally occuring bacteria that keeps yeast at bay. It doesn't happen in all women taking Doxy but it is one of the side effects of which you should be aware. I would recomend taking an over the counter treatment along just to have on hand. It won't take up a lot of room in your pack. As I commented in a PM to another member, yes - OTC treatments are available around the world, but if you happen to develop a yeast infection while roaming around in a more remote area, it could be an uncomfortable few days before you are able to remedy the situation.
There is one other piece of information women taking oral contraceptives and planning to use Doxy for prophylaxis should know. Doxy can decrease the effectiveness of the oral contraceptives for a relatively short period of time. Doxy does not render OCs completely ineffective but can decrease them to a 75-80% effectiveness level (approximately). Other forms of birth control should be used during the first 4 weeks of Doxy administration. During that month, OC levels do return to their pre-Doxy state and the other birth control method can be discontinued.