This information is available from the UK HPA, WHO or CDC (links are given below). Doses depend also on what is available (e.g., in the US, mefloquine tablets contain 228 mg base, but 250 mg base in the UK). The data is constantly changing and no general advice is possible. Doses given are appropriate for adults and children aged 12 and over. Other chemoprophylactic regimens that have been used on occasion:

Dapsone 100 mg and pyrimethamine 12.5 mg once weekly (available as a combination tablet called Maloprim or Deltaprim): this combination is not routinely recommended because of the risk of agranulocytosis;
Primaquine 30 mg once daily (started the day before travel, and continuing for seven days after returning): this regimen is not routinely recommended because of the need for G-6-PD testing prior to starting primaquine (see the article on primaquine for more information). Quinine sulfate 300 to 325 mg once daily: this regimen is effective but not routinely used because of the unpleasant side effects of quinine.Prophylaxis against Plasmodium vivax requires a different approach given the long liver stage of this parasite. This is a highly specialist area. Vaccines
In November 2012, findings from a Phase III trials of an experimental malaria vaccine known as RTS,S reported that it provided modest protection against both clinical and severe malaria in young infants.
There is very low quality evidence indicating that doxycycline use may be associated with an increased risk of indigestion, photosensitivity, vomiting, and yeast infections, when compared with mefloquine and atovaquone-proguanil. Causal prophylaxis
Causal prophylactics target not only the blood stages of malaria, but the initial liver stage as well. This means that the user can stop taking the drug seven days after leaving the area of risk. Malarone and primaquine are the only causal prophylactics in current use. Regimens
Specific regimens are recommended by the WHO, UK HPA and CDC for prevention of P. falciparum infection. HPA and WHO advice are broadly in line with each other (although there are some differences). CDC guidance frequently contradicts HPA and WHO guidance. These regimens include:

doxycycline 100 mg once daily (started one day before travel, and continued for four weeks after returning);
mefloquine 250 mg once weekly (started two-and-a-half weeks before travel, and continued for four weeks after returning);
atovaquone/proguanil (Malarone) 1 tablet daily (started one day before travel, and continued for 1 week after returning). Can also be used for therapy in some cases.In areas where chloroquine remains effective:

chloroquine 300 mg once weekly, and proguanil 200 mg once daily (started one week before travel, and continued for four weeks after returning);
hydroxychloroquine 400 mg once weekly (started one to two weeks before travel and continued for four weeks after returning)What regimen is appropriate depends on the person who is to take the medication as well as the country or region travelled to.