GLP-1 Receptor Agonists (Class Overview)

What This Medicine Does

GLP-1 receptor agonists are a modern class of medicines that work in several ways to help manage diabetes and weight:

1. Signal fullness to your brain - You feel satisfied with smaller portions
2. Slow stomach emptying - Food stays in your stomach longer, keeping you full
3. Boost insulin when needed - Your body releases the right amount of insulin after meals
4. Reduce excess sugar production - Your liver makes less glucose

The result: Better blood sugar control, reduced appetite, and meaningful weight loss for many people.

What to Expect: A Timeline

Week 1-2: Getting Started

You'll begin at a low dose to minimize side effects. You may feel:

• Mild nausea or fullness
• Less interest in food
• Slight changes in bowel habits

Week 3-4: Adjusting

As your dose increases, you may notice:

• Reduced appetite
• Early satiety (feeling full sooner)
• Steady weight loss beginning
• Improved energy levels

Week 8-12: Full Effect

By now, you should experience:

• Noticeable weight loss
• Better blood sugar readings
• Reduced food cravings
• Stabilized side effects (most improve over time)

Ongoing: Maintenance

• Continue monthly or weekly dosing
• Regular check-ups with your healthcare team
• Monitor for long-term side effects

Common Things You Might Notice

Gastrointestinal Effects (Very Common):

• Nausea - Affects up to 40% of people, usually improves after 4-6 weeks
• Feeling full quickly - This is actually a desired effect that helps with weight loss
• Constipation - Drink plenty of water and eat fiber-rich foods
• Diarrhea - Usually mild and temporary

Other Common Effects:

• Headache (especially when starting)
• Mild fatigue
• Injection site reactions (redness, itching)

Good News: These side effects often decrease as your body adjusts to the medicine.

Tips for Managing Nausea

Nausea is the most common reason people stop these medicines. Here's how to manage it:

1. Eat slowly - Take small bites and chew thoroughly
2. Stop before full - Put your fork down when you feel 80% full
3. Choose bland foods - crackers, toast, rice, bananas when nauseated
4. Avoid triggers - greasy, spicy, or very sweet foods
5. Stay hydrated - Sip water throughout the day
6. Time your dose - If taking weekly injections, choose a day that works best for your schedule

When to Call Your Doctor

Seek Immediate Care For:

• Severe, persistent abdominal pain (especially pain that radiates to your back) - This could indicate pancreatitis
• Vomiting that won't stop - Can lead to dangerous dehydration
• Difficulty breathing or swallowing - Possible allergic reaction
• Severe dizziness or confusion - Could indicate very low blood sugar

Contact Your Doctor Soon For:

• Nausea that prevents you from eating or drinking for more than 24 hours
• Yellowing of your skin or eyes (gallbladder issues)
• New or worsening depression or thoughts of self-harm
• Unusual lumps or swelling in your neck (thyroid concerns)

Daily Practical Tips

1. Pick a consistent day - For weekly injections, choose the same day each week (e.g., Sunday mornings)

2. Rotate injection sites - Use your abdomen, thigh, or upper arm; don't use the exact same spot twice in a row

3. Store properly - Refrigerate unused pens; room temperature is fine for the pen in use (up to 56 days for most)

4. Plan meals - Eat smaller, more frequent meals to manage fullness

5. Track your progress - Keep a log of weight, blood sugar readings, and side effects

6. Stay connected - Regular follow-ups with your healthcare team are important

Food & Medicine Interactions

Oral Semaglutide Special Instructions

If taking Rybelsus (oral semaglutide):

• Take on an empty stomach with a small glass of water
• Wait at least 30 minutes before eating, drinking, or taking other medicines
• No more than 4 ounces of plain water with the tablet

Insulin & Sulfonylureas

If combining with these diabetes medicines:

• Your doctor may lower your dose
• Risk of low blood sugar increases
• Monitor blood sugar more frequently

For Healthcare Professionals

Pharmacology & Mechanism

GLP-1 RAs activate the GLP-1 receptor, enhancing glucose-dependent insulin secretion, suppressing glucagon secretion, slowing gastric emptying, and reducing appetite through central nervous system pathways.

Available Agents & Dosing

Titration Schedule (Weekly Semaglutide/Tirzepatide)

Monitoring Requirements

Baseline:

• HbA1c, fasting glucose
• Weight, BMI
• Renal function (eGFR)
• Thyroid evaluation (if personal/family history of medullary thyroid carcinoma or MEN2)

Follow-up (every 3 months):

• HbA1c
• Weight
• Renal function (if at risk)
• Medication tolerance and side effects

Contraindications & Warnings

Boxed Warnings:

• Medullary thyroid carcinoma (MTC) - Contraindicated in personal or family history
• Multiple Endocrine Neoplasia syndrome type 2 (MEN2) - Contraindicated

Other Contraindications:

• Prior serious hypersensitivity to semaglutide or any component
• Pregnancy (discontinue at least 2 months before planned pregnancy)

Warnings & Precautions:

• Pancreatitis - Discontinue if suspected; do not restart
• Gallbladder disease - Monitor for cholecystitis symptoms
• Hypoglycemia risk - Increased when combined with insulin/sulfonylureas
• Acute kidney injury - Risk increased with severe nausea/vomiting/dehydration
• Diabetic retinopathy complications - Use caution in patients with history
• Suicidal behavior and ideation - Monitor for new or worsening depression

Drug Interactions

Efficacy Data

Glycemic Control:

• HbA1c reduction: 1.0-1.8% (monotherapy)
• Superior to most other antihyperglycemic agents

Weight Loss:

• Semaglutide 2.4 mg: ~15% body weight reduction at 68 weeks (STEP trials)
• Tirzepatide 15 mg: ~20% body weight reduction at 72 weeks (SURMOUNT-1)

Cardiovascular:

• Semaglutide: 26% reduction in MACE (SUSTAIN-6)
• Liraglutide: 13% reduction in MACE (LEADER)

Medical Disclaimer: This content is for educational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider before starting, stopping, or changing any medication.