SGLT2 Inhibitors and Dry Mouth/Constipation
Dry mouth and constipation are not recognized adverse effects of SGLT2 inhibitors based on major clinical trials and guideline safety profiles. These symptoms are not listed among the documented side effects in comprehensive safety analyses from large randomized controlled trials or expert consensus guidelines 1.
Documented Adverse Effects of SGLT2 Inhibitors
The well-established side effect profile of SGLT2 inhibitors includes:
Common Adverse Effects
- Genital mycotic infections are the most common side effect, occurring in approximately 6% of users versus 1% on placebo, typically presenting as candida vaginitis in women and balanitis in men 1, 2
- These infections are generally mild, resolve with brief antifungal courses, and rarely recur 1
- Volume depletion and hypotension can occur due to the osmotic diuretic effect, particularly in elderly patients, those on concurrent diuretics, or patients with low baseline blood pressure 1, 3
Rare but Serious Adverse Effects
- Euglycemic diabetic ketoacidosis is a rare but potentially life-threatening complication, though the risk is very low in large randomized trials, especially in patients not requiring insulin 1, 4
- Urinary tract infections do not occur at higher rates compared to placebo in large clinical trials, despite theoretical concerns about glycosuria 2
- Canagliflozin specifically has been associated with increased risk of lower limb amputation (6.3 vs 3.4 per 1,000 patient-years) and bone fractures, though this has not been consistently observed with other SGLT2 inhibitors 1
Why Dry Mouth and Constipation Are Not Associated
The mechanism of action of SGLT2 inhibitors—blocking glucose reabsorption in the proximal renal tubule—does not affect salivary gland function or gastrointestinal motility 5, 6. The comprehensive safety reviews from the American College of Cardiology and Mayo Clinic guidelines do not mention dry mouth or constipation among adverse effects 1.
Clinical Implications
If a patient on SGLT2 inhibitors reports dry mouth or constipation, consider:
- Alternative medication causes: Review other medications that commonly cause these symptoms (anticholinergics, opioids, antihistamines)
- Dehydration from volume depletion: The diuretic effect could theoretically contribute to dehydration symptoms, though this would typically present with orthostatic symptoms rather than isolated dry mouth 3
- Unrelated conditions: Diabetes itself can cause dry mouth through autonomic neuropathy or poor glycemic control 6