What it is
Pramlintide is a 37-amino-acid copy of amylin — a hormone the pancreas releases from the same beta cells, and at the same moments, as insulin. People with type 1 diabetes make almost none; people with advanced type 2 make too little. Sold as Symlin, it was approved on 16 March 2005 as the first drug ever to act on amylin receptors.
Its molecular weight is 3,949.4. The Symlin label spells out the one thing that makes it different from the human hormone:
| Position | Human amylin | Pramlintide |
|---|---|---|
| 25 | Alanine | Proline |
| 28 | Serine | Proline |
| 29 | Serine | Proline |
Those three prolines are the rat's. Human amylin clumps into amyloid fibrils — the deposits found in the pancreas in type 2 diabetes — and cannot be kept in solution as a drug. Rat amylin, with prolines at the same three positions, does not. Pramlintide borrowed the rat's fix and kept the rest of the human sequence.
How it works
Amylin acts after a meal, and so does pramlintide. It slows stomach emptying, suppresses the glucagon surge that normally follows eating, and reduces appetite through the brainstem. It is not an insulin substitute and does not act on the GLP-1 receptor; it is a second hormone that insulin injections leave out.
The Symlin label's pharmacokinetics show why it was a mealtime drug: absolute bioavailability under the skin of 30–40%, and a half-life of 48 to 55 minutes across its single-dose table.
What it was approved for
One indication: an add-on for people with type 1 or type 2 diabetes who use mealtime insulin and have not reached their glucose targets despite optimal insulin therapy. It is not approved for weight loss, and it was never approved without insulin.
Doses on the label
Reported as the Symlin label states them, not as guidance. Type 1 diabetes: 15 mcg before major meals, raised in 15 mcg steps to 30 or 60 mcg. Type 2 diabetes: 60 mcg, raised to 120 mcg. For both, the label directs a 50% cut in mealtime insulin when pramlintide is started and at least three days between steps, to limit nausea.
Safety
The Symlin label carries a boxed warning for severe hypoglycaemia: with insulin, especially in type 1 diabetes, it has appeared within 3 hours of an injection, and the label flags the danger of it striking while driving or operating machinery. Patient selection, instruction and the insulin reduction are named as the ways to lower the risk. Nausea is the commonest everyday effect.
Where it stands
FDA application data list all three Symlin presentations as discontinued on 2026-09-27, and there is no generic. ClinicalTrials.gov holds 64 records with pramlintide as an intervention; Europe PMC's MEDLINE index holds 430 records naming it in the title or abstract, 64 tagged as randomised controlled trials.
The drug is close to gone; the idea is not. The amylin analogues now in trials for weight — cagrilintide and eloralintide — are pramlintide's direct descendants, redesigned to last a week instead of an hour.
Related reading
Pramlintide was approved six weeks before exenatide, and the two came from the same developer. For the amylin receptor's newer drugs, see cagrilintide, which is paired with semaglutide in CagriSema, and eloralintide, a receptor-selective weekly analogue in phase 3.