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The labels of approved peptide drugs are the best source for understanding which risks are considered inherent to each class. Although research material is not that drug, class warnings describe the biology of the mechanism.
GLP-1 agonists and related compounds
- Thyroid C-cell tumors: observed in rodents. Labels contraindicate these drugs in people with a personal or family history of medullary thyroid carcinoma or MEN 2 syndrome.
- Pancreatitis: a class warning; treatment is stopped if persistent abdominal pain suggests it.
- Gallbladder disease: associated in part with rapid weight loss.
- Diabetic retinopathy: in people with pre-existing retinopathy, a rapid improvement in blood glucose has been associated with transient worsening.
- Slow gastric emptying: relevant before procedures under sedation and for oral drugs with a narrow margin.
GH/IGF-1 axis
- Active neoplasia: a recurring contraindication because of the mitogenic role of IGF-1.
- Glucose metabolism: GH is counter-regulatory (it can raise glucose); IGF-1 can lower it.
- Fluid retention, paresthesias and arthralgias: dose-dependent effects.
Melanocortins
- Changes in nevi (moles): darkening and appearance of pigmented lesions; requires dermatological monitoring.
- Blood pressure: transient elevation described with bremelanotide.
Angiogenic compounds
Compounds whose described mechanism includes stimulation of angiogenesis (for example, via VEGFR2) raise an open question in the presence of undiagnosed neoplasia, because vascularization is a requirement for tumor growth. There are no data showing a risk, but none ruling it out either.
Pregnancy and breastfeeding
Virtually no research peptide has data in pregnancy. The labels of approved drugs in the metabolic classes recommend stopping them before a planned conception. The absence of data is interpreted as absence of demonstrated safety.
Class contraindications apply to the mechanism, not the brand. If a mechanism carries a warning on its approved drug, the same biology applies when studying any molecule that acts through that pathway.
Catalogue compounds mentioned in this lesson
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