Can Lamasil increase blood sugar level?

Having high blood sugar is not a known side effect of Lamisil, actually it may cause hypoglycemia (low blood sugar).

The known side effects of Lamisil are:

Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Lamisil:

Diarrhea; headache; indigestion; taste changes.

Seek medical attention right away if any of these SEVERE side effects occur when using Lamisil:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue; unusual hoarseness); red, blistered, peeling, or swollen skin; symptoms of infection (eg, fever, chills, sore throat); symptoms of liver problems (eg, dark urine; loss of appetite; pale stools; stomach pain; unexplained, persistent nausea; unusual tiredness; vomiting; yellowing of the skin or eyes); unusual bruising or bleeding; vision changes.

https://www.drugs.com/sfx/lamisil-side-effects.html

If your sugar levels are high continuously then please see your doctor.