Can insulin Humalog or Lantis cause lethargy and drowsiness?

I believe you are correct. I checked on line and Humalog can cause muscle weakness, especially in women. Lantis lasts 24 hours and Humalog lasts a max of 5 1/2 hours they are noth insulin but act differently in people. I am glad that your mom is not affected by lantis. Thanks for the feedbadk.

My mother and neighbor have taken Lantis without becoming drowsy. High blood sugar can make some people drowsy. Boredom can also do it. I would suspect those before I would the Lantis.