Alcohol has a similar effect. After Inactivity especially bedrest. When Constipated, the effort of 'straining' causes symptoms, they can also occur when coughing or if there is any effort involved in passing urine. Illness, from a cold to more serious conditions. An increase in symptoms may be a sign of illness.
Anxiety can cause overbreathing which lowers blood pressure.
A variety of Drugs can lower blood pressure, always check new medication with your doctor Management. The aim of management is to minimise the effects of low blood pressure. This is done using preventative measures and strategies for use in various situations. The result should produce a positive effect on your lifestyle. There are a variety of drugs that can raise blood pressure.