What the FDA labels say about taking them together
Demeclocycline and vasopressin
Vasopressin's FDA label of February 21, 2025 names demeclocycline in its drug interactions section; the demeclocycline label PlainMeds reads does not name vasopressin. The vasopressin label: “Suspected of Causing Diabetes Insipidus Use with drugs suspected of causing diabetes insipidus may decrease the pressor effect in addition to the antidiuretic effect of Vasostrict ®.”
Check it at the source: the demeclocycline FDA label on DailyMed (effective April 2, 2026, Amneal Pharmaceuticals of New York LLC); the vasopressin FDA label on DailyMed (effective February 21, 2025, Baxter Healthcare Corporation).
What does the demeclocycline label say about vasopressin?
Demeclocycline's label (effective April 2, 2026) does not name vasopressin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Demeclocycline Hydrochloride), Amneal Pharmaceuticals of New York LLC, effective April 2, 2026 (SPL set 539add06-e0a0-401a-b4f6-20776084aa9c), via openFDA; the full label on DailyMed
What does the vasopressin label say about demeclocycline?
Vasopressin label, drug interactionsSuspected of Causing Diabetes Insipidus Use with drugs suspected of causing diabetes insipidus (e.g., demeclocycline, lithium, foscarnet, clozapine) may decrease the pressor effect in addition to the antidiuretic effect of Vasopressin in Sodium Chloride Injection.
Source: FDA drug label (Vasostrict, NDA204485), Par Health USA, LLC, effective April 21, 2026 (SPL set b1147beb-743e-4c62-8927-91192447f8b8), via openFDA
Source: FDA drug label (Vasopressin, NDA212593), American Regent, Inc., effective October 31, 2024 (SPL set 0ab267f4-9ec9-44fd-8521-f975074667d9), via openFDA
Source: FDA drug label (Vasopressin in 0.9% Sodium Chloride), Baxter Healthcare Corporation, effective February 21, 2025 (SPL set b5b2c367-6b7e-40be-a296-c4632f3e783f), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Demeclocycline | Vasopressin | |
|---|---|---|
| Labeled for | Bacterial infections, Urinary tract infections | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $2.27 per tablet 150 mg tablet | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once