Blood sugar level 250-400 mg/dl (mmol/l)

very high blood sugar levelsvery high blood sugar levels

When your blood sugar was tested...

you found your levels ranging 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399.

Having blood sugar level 250-400 mg/dl, regardless if having eaten or not, means you suffer from mild to moderate diabetes.

NORMAL or DANGEROUS    Type Your Blood sugar Level:    mg/dl

Causes of Blood sugar level 250-400 mg/dl

Apart diabetes, and some illness, such levels of glucose may also be due to the intake of specific medicines such as steroids, beta blockers, antipsychotics, pentamidine etc.

You can click in the following sections to find out the detailed information of eating, after eating and drug-induced levels of glucose 250-400 mg/dl.

Very High Blood Sugar Level 250-400 mg/dL - SYMPTOMS 

Usually, symptoms of diabetes are evident when glucose in the bloodstream reaches the levels above 250 mg/dl. If you have just found out you have diabetes, start treatment immediately.

You might experience extreme fatigue, frequent urination, and dry mouth. 

Blood sugar levels 250-400 mg/dl are usually not an indication for hospitalization, so you most probably should consult with your doctor about the proper anti-diabetic therapy.

My patient's case: Random blood sugar 400 and as low as 157 


Three weeks before, my husband random blood sugar level is 400 but now 157.  Is this good or bad?

Aimee, Maldives

Answer: Hello Aimee,

Random glucose testing is important to distinguish how effective the treatment is. In diabetic people, the numbers for random glucose levels may vary widely. 

The comparison between days is not the right one. Take the random glucose test multiple times during a day and compare the numbers. 

In a diabetic person, they may vary more than in normal people but they must not vary too widely. If they do vary a lot this means that the treatment is not effective or your husband is not following it.

The glucose levels must stay relatively stable as much as possible. Also, stress, diet and the time of the time may influence the results.

It is important to control diabetes in order to prevent serious complications in the future and current symptoms.

Hope this is helpful for your husband.

Blood sugar levels 250-400 mg/dl induced by drugs

In some cases, the  blood sugar levels can reach as high as  250-400 mg/dl induced by certain drugs such as Thiazines, beta blockers, statins, steroids, antipsychotics, immunosuppressive agents, pentamidine, nicotinic acid etc.

The increased levels of glucose may be because of the increase of insulin resistance, or due to the affection of insulin secretion, or both.

The symptoms of blood sugar levels 250-400 mg/dl induced by drugs

The symptoms are the same as for diabetes but with the difference of the time when they might appear. So, you might notice them shortly after taking the drug, or even after taking it for a long time.

Sometimes it takes a few days after the initial start of the drugs for the symptoms to appear

Treatment Strategy

The very first thing to do when you catch your blood sugar levels high and are taking that particular medication, is to stop using the drugs.

If after being off the drug, the increased glucose numbers persist, then a further consultation with  your doctor for further confirmatory tests. Perhaps, you may need to start an anti-diabetic treatment for a short period only until improvement of glucose levels.

Patient's Case: Hi, My mother is 88 yrs old. She has been taking Glyree M1 after breakfast only. Her Fasting sugar was 112 and PP/ after 2 hrs after b'fast was 284 and 264 consequently for two days Is there any cause for concern or change of medication required. Vijay

Answer: Hi, Your mother's blood sugar levels after eating breakfast is considered really high for her age. need to change medication. Please provide the names of meds she is currently taking. 

Thank you. 

Patient's case: Hello doctor my blood sugar level is 250 mg what to do? (by Riya Lotlikar - GOA)

Answer: Hi, If your blood sugar is 250 mg when measured randomly is a bit high. However, it depends on what you have eaten? the time of measurement? 

Take another test fasting and run HbA1C test to determine the average of blood glucose the last three months. 

For the moment, try to make some changes in your diet and lifestyle regimen. Start taking some natural remedies for diabetes

Thank you.

Prevention of having high blood sugar levels 250-400 mg/dL

If left untreated, it will cause serious health issues. The most common long-term complications of these levels of blood glucose can cause kidney failure, heart problems such as heart attacks, brain problems such as strokes, can damage the nerves of inferior limbs, can damage the eyes and may even cause total blindness.

If prediabetic, prevention can be done by making the lifestyle changes as described above.

If you know you have diabetes, continue with the lifestyle changes and with the correct and punctual intake of your drugs. Be sure to measure your glucose level three times a day.

In case the increased blood glucose was caused by certain medications, then should not use these drugs again.

If you must use these drugs, consult with your doctor first, and tell your previous history with spikes in blood sugar.  

He might come up with a plan to avoid your glucose levels to rise while using this drug.

Take-Home Tips

  • Blood sugar levels of 250 to 400 are considered very high and dangerous. 
  • Causes include: uncontrolled diabetes; taking some medications like steroids, antipsychotics, betablockers, etc.
  • Symptoms are similar to diabetes: increased thirst and urination, etc.
  • Treatment is by treating the underlying condition. 


Last review 12/29/2018

Ask Diabetes Questions and get a reply from a real medical doctor

New! Comments

Ask A question Or Leave a comment.

blood sugar level 11-44 After eating

blood sugar level 11-44 Fasting

blood sugar level 11-44 After medication

Blood glucose level 45-69

Blood glucose level 45-69

Blood glucose level 45-69

Blood glucose level 70 -109

Blood glucose level 70 -109

Blood glucose level 70 -109

Blood glucose level 110-126

Blood glucose level 110-126

Blood glucose level 110-126

Blood glucose level 250-400

Blood glucose level 250-400

Blood glucose level 250-400

Blood glucose level 127-200

Blood glucose level 127-200

Blood glucose level 127-200

Blood glucose level over400

Blood glucose level over400

Blood glucose level over400

Blood glucose level 200-250Blood glucose level 200-250

Blood glucose level 200-250

Blood glucose level 200-250

Blood glucose level 200-250

› Blood sugar level 250-400 mg/dl