I took a magnesium pill (250 mg) and during the night i noticed that i started to get high blood pressure and it continuted on to the next day. Is it because of the magnesium or something else?
Magnesium did not cause your high blood pressure.
Hypermagnesemia is an electrolyte disturbance in which there is an abnormally elevated level of magnesium in the blood. Usually this results in excess of magnesium in the body.
Hypermagnesemia occurs rarely because the kidney is very effective in excreting excess magnesium. It usually develops only in people with kidney failure who are given magnesium salts or who take drugs that contain magnesium (e.g. some antacids and laxatives). It is usually concurrent with hypercalcemia and/or hyperkalemia.
Symptoms include: Weakness, nausea and vomiting, Hypotension, Impaired breathing, Arrhythmia and asystole, most prominent cardiac symptoms are due to conduction delays, since magnesium acts as physiologic calcium blocker.

4 comments ↓
Might be anxiety, my profile under anxiety has more. If I remember correctly no the supplement should not cause high bp. I take the pill as well and have had no probs. Might be worth further investigations.
References :
It’s likely something else. Magnesium is a muscle relaxer. High blood pressure is caused by many things including emotion (anger), diet, obesity… Since it was something you noticed at a specific time, you might look at what you ate & were thinking about then…
However, why were you taking the magnesium? You should try to balance your potassium levels to your magnesium levels…
All the best….
References :
It must be something else because magnesium can actually cause low blood pressure
References :
Magnesium did not cause your high blood pressure.
Hypermagnesemia is an electrolyte disturbance in which there is an abnormally elevated level of magnesium in the blood. Usually this results in excess of magnesium in the body.
Hypermagnesemia occurs rarely because the kidney is very effective in excreting excess magnesium. It usually develops only in people with kidney failure who are given magnesium salts or who take drugs that contain magnesium (e.g. some antacids and laxatives). It is usually concurrent with hypercalcemia and/or hyperkalemia.
Symptoms include: Weakness, nausea and vomiting, Hypotension, Impaired breathing, Arrhythmia and asystole, most prominent cardiac symptoms are due to conduction delays, since magnesium acts as physiologic calcium blocker.
References :
http://en.wikipedia.org/wiki/Hypermagnesemia