Guidelines on dose modification for diabetics doing intermittent fasting

1. Appendix
(Based on recommendation from IDF-DAR Diabetes and Ramadan:Practical Guidelines)
This guidelines are those for T2D patients doing intermittent fasting (IF) for 16 hours (eg from 8.00
pm till 12.00 noon the next day) with 8 hours eating window (eg 12.00 noon – 8.00 pm). Simply they
are advised to skip breakfast, but can take plain water/tea/coffee without sugar
Patients usually advised to take heavier meal during lunch (60-70% of total calorie) with the
remaining taken during dinner.
The meals consist of very low carbohydrate high fat diet (5-10% carb, 70-80% fat, 20-25% protein).
Net carb (Total carb-fibre) < 50 gm/day.
Suggestions for Dose Adjusment of medications:
Oral Anti-Diabetic Agents:
1. Metformin
OD dose BD dose TDS dose Prolonged release
No dose medication
usually required
No dose medication
usually required
Combine morning dose
with dose taken at
lunch
No dose modification
usually required
Take at lunch Take at lunch & dinner Take night dose as
usual at dinner
Take at lunch
2. Acarbose – no dose modification
3. Thiazolidinediones – no dose modification
4. Short acting insulin secretagogues (repaglinide, nateglinide)-dose may be reduced or re-
distributed to two doses, according to meal size
5. Sulphonylureas – associated with higher risk of hypoglycaemia
OD dose BD dose Older drugs in the class
Take at lunch Lunch dose remains the same Older drugs eg glibenclamide
carry a higher risk of
hypoglycaemia and should be
avoided
In patients with well
controlled BG, the dose may
be reduced
In patients with well-controlled
BG, the night dose should be
reduced
2nd
gen SU (gliclazide,
glimepiride) should be used in
preference

2. 6. SGLT-2 inhibitors – no dose adjustment
7. DPP-4 inhibitors – no dose adjustment
Insulin Treatment for T2DM
This may include the use of a long acting/intermediate acting basal insulin (insulin glargine, insulin
determir or NPH insulin), possibly with a rapid or short-acting bolus/pre-meal insulin (lispro, aspart
or regular human insulin)
Changes to long and short acting insulin dose during IF
Long/intermediate-acting (basal insulin) Short acting insulin
NPH/detemir/glargine/degludec once
daily
Reduce dose by 15-30%
Take at lunch
Omit morning dose
Normal dose at lunch
Reduce dinner dose by 25-50%
NPH/determir/glargine twice-daily
Take usual morning dose at lunch
Reduce evening dose 50% and take at dinner
Dose modification based on dextrostix:
Fasting/pre-lunch/pre-dinner
dxt
Pre-lunch Pre-lunch/pre-dinner
Basal insulin Short acting insulin
< 3.9 mmol/L or symptoms Reduce by 4 units Reduce by 4 units
3.9-5.0 mmol/L Reduce by 2 units Reduce by 2 units
5.0-7.2 mmol/L No change required No change required
7.2-11.1 mmol/L Increase by 2 units Increase by 2 units
>11.1 mmol/L Increase by 4 units Increase by 4 units

3. Changes to pre-mixed insulin dosing during intermittent fasting
Once daily dosing Twice daily dosing Three times daily
dosing
Take normal dose at
lunch
Take normal dose at
lunch
Omit morning dose.
Adjust lunch and
dinner dose
Reduce dinner dose by
25-50%
Carry out dose titration
every 3 days (see
below)
Fasting/pre-lunch/pre-dinner dxt Pre-mixed insulin modification
<3.9 mmol/L or symptoms Reduce by 4 units
3.9-5.0 mmol/L Reduce by 2 units
5.0-7.0 mmol/L No change required
7.0-11.1 mmol/L Increase by 2 units
>11.1 mmol/L Increase by 4 units