Short answer: They can add to the risk. The Contrave label says weight loss may raise the risk of low blood sugar in type 2 diabetes treated with insulin or sulfonylureas, and recommends glucose checks before and during treatment. The phentermine (Lomaira) label says insulin or diabetes pill doses may need to come down. The Qsymia label asks for glucose checks in people with type 2 diabetes on diabetes medicines.
| Medicine | What the label says |
|---|---|
| Contrave (naltrexone and bupropion) | Weight loss may raise the risk of low blood sugar with insulin or insulin secretagogues such as sulfonylureas. Glucose checks before and during treatment are recommended, and lower doses of those medicines considered (section 5.10) |
| Lomaira (phentermine) | A reduction in insulin or oral diabetes medicines may be required (Warnings); requirements may be altered (Drug Interactions) |
| Qsymia (phentermine and topiramate) | Glucose is checked before starting and periodically during treatment in people with type 2 diabetes on diabetes medicines (section 2.1) |
Contrave is approved for long-term weight management, while Lomaira is approved for short-term use of a few weeks, so the length of overlap with diabetes medicines differs. The Contrave label adds that if low blood sugar happens after starting, the diabetes treatment is changed. The dose cut it describes is for diabetes medicines that are not glucose-dependent.
NIDDK says low blood glucose can be a side effect of insulin and of two types of diabetes pills: sulfonylureas, which raise insulin over several hours, and meglitinides, taken before meals. Not eating or drinking enough carbohydrates can also lower blood glucose.
NIDDK lists mild-to-moderate symptoms such as feeling shaky, hungry, tired, dizzy, confused or irritable, a fast or uneven heartbeat, and headache. Very low levels can cause seizures or loss of consciousness. NIDDK notes that glucose can also drop during sleep, with signs such as nightmares, sweating through sheets, or waking tired or confused. See hypoglycemia and sulfonylurea.
GLP-1 medicines have their own wording on this; see can GLP-1 medicines cause low blood sugar.
People on insulin or a sulfonylurea who start a weight-loss pill can ask who will adjust the diabetes medicines, what glucose readings should prompt a call, and how often to check. Dose Track logs insulin doses and the weight-loss medicine side by side, with glucose notes, so a pattern of lows after a dose change is easy to show.
Read more on Dose Track: Contrave side effects · Qsymia side effects · Lomaira side effects · Hypoglycemia