Lotak A is commonly used to control high blood pressure and usually contains a mixture of losartan and amlodipine. Substitute medicines may be available with the same ingredients and strength, but the replacement must properly match your current dose and medical condition. Many people switch to another brand with the same salt mixture when advised by a doctor or pharmacist. The correct substitute depends on your blood pressure control, kidney function, swelling history, dizziness and other medications you may be taking. Some people tolerate one brand better than the other, even if the ingredients are similar. Blood pressure should be monitored after changing brands because sudden switching may occasionally affect control. Do not stop or replace the medicine suddenly if your blood pressure is stable. If you are experiencing side effects such as leg swelling, severe dizziness, fatigue, or palpitations, the treatment plan may need adjustment rather than just a brand substitute.