Tirzepatide (Zepbound) – A New Treatment for Obstructive Sleep Apnea and Obesity
In December 2024, the FDA approved Tirzepatide (Zepbound) for treating moderate-to-severe obstructive sleep apnea (OSA) in adults with obesity. This marks a significant milestone as Tirzepatide is the first prescription drug approved for OSA. Initially launched in 2023 for obesity-related conditions, its potent weight loss effects (20-25% body weight reduction) make it a promising solution, given that excess weight is a leading risk factor for OSA in 75-80% of cases.
OSA is prevalent among adults with Type 2 diabetes, further increasing the relevance of Tirzepatide. Clinical trials demonstrated a reduction of 25 respiratory events per hour, with up to 50% of patients achieving symptom resolution after a year. However, long-term data remains limited.
How Tirzepatide Works: A Dual Receptor Agonist
Tirzepatide operates by activating two key metabolic receptors:
GLP-1 (Glucagon-Like Peptide-1)
GIP (Gastric Inhibitory Polypeptide)
Both hormones play essential roles in metabolism, influencing insulin secretion, appetite suppression, and weight loss. GLP-1 slows gastric emptying, inhibits glucagon release, and enhances insulin sensitivity. GIP, on the other hand, links nutrient intake to energy storage and insulin regulation.
How Glucagon Works: The Body’s Blood Sugar Regulator
Glucagon is a hormone produced by the pancreas that plays a counter-regulatory role against insulin:
Released when blood sugar is low, such as during fasting or exercise.
Acts on the liver to increase blood glucose levels via two processes:
Glycogenolysis: Breakdown of glycogen into glucose.
Gluconeogenesis: Creation of new glucose from non-carbohydrate sources (e.g., amino acids, lactate).
Also affects fat tissue, promoting fat breakdown (lipolysis) for energy.
Works opposite to insulin, ensuring stable blood sugar levels.
GLP-1 Receptor Agonists: Mechanism and Benefits
GLP-1 receptor agonists are medications that mimic the effects of the natural GLP-1 hormone, which is secreted by the intestines in response to food. These drugs are used to treat Type 2 diabetes and, more recently, obesity.
Key Actions of GLP-1 Agonists
Suppress Appetite: Reduce hunger signals in the brain.
Enhance Insulin Release: Stimulate insulin secretion only when glucose levels are elevated.
Slow Gastric Emptying: Prolong feelings of fullness after meals.
Reduce Glucagon Secretion: Prevent excessive glucose production by the liver.
Available GLP-1 Agonists
Among these, Tirzepatide is unique because it activates both GLP-1 and GIP receptors, resulting in stronger weight loss effects than semaglutide.
Gastric Inhibitory Peptide (GIP)
GIP is a hormone that regulates digestion and glucose metabolism. It is part of the incretin system, which enhances insulin secretion after meals.
Key Functions of GIP
Produced by the K cells of the small intestine.
Stimulates insulin secretion, helping cells absorb glucose.
Supports fat metabolism, promoting energy storage.
Interacts with GLP-1, with complementary but distinct effects.
In Type 2 diabetes, the body’s response to GIP is often impaired, which contributes to poor glucose control. Dual GLP-1/GIP agonists like Tirzepatide leverage both hormones for better metabolic regulation.
Tirzepatide’s Role in OSA Treatment
Tirzepatide represents an additional treatment option for BetterNight patients with moderate-to-severe OSA and obesity. However, it is not a replacement for traditional OSA therapies, such as:
CPAP (Continuous Positive Airway Pressure)
Oral appliances
Since OSA severity does not always correlate directly with symptoms, documenting reductions in respiratory events is crucial before discontinuing conventional treatments. In severe cases, even reducing 25 events per hour may still leave a patient with significant OSA.
Conclusion
Tirzepatide’s approval as the first drug for OSA expands treatment options for patients with both obesity and sleep apnea. Its ability to reduce weight significantly and improve metabolic health makes it a breakthrough therapy. However, while promising, its long-term effects on OSA outcomes beyond weight loss require further study. For now, it serves as a complementary therapy rather than a complete replacement for traditional OSA treatments.