Final answer:
Prevention of preeclampsia primarily involves the use of daily low-dose aspirin for women at high risk, starting from the late first trimester, and intravenous magnesium sulfate during preeclampsia to prevent eclampsia.
Step-by-step explanation:
Pharmacological therapy used to prevent preeclampsia involves the use of daily low-dose aspirin (75 to 150 mg) starting from late first trimester for women at high risk of preeclampsia. This is prescribed as a preventive measure to thwart the development of the condition. Aspirin is known to have antiplatelet effects and may help by improving the blood flow within the placenta. In addition to aspirin, intravenous magnesium sulfate is not used to prevent preeclampsia but rather to prevent the progression to eclampsia in women who have developed preeclampsia, as it has been proven effective in preventing seizures. Oral antihypertensive medications, such as calcium channel blockers, beta blockers, or other antihypertensive drugs, are not primarily used to prevent preeclampsia but are used in its management if high blood pressure ensues. It's crucial to note that the use of any medication during pregnancy should be under the strict supervision of a healthcare provider.