1. Introduction
Sitagliptin is an oral anti-diabetic medication belonging to the dipeptidyl peptidase-4 (DPP-4) inhibitor class. It is used in the management of type 2 diabetes mellitus (T2DM) to improve blood sugar levels. Sitagliptin enhances the activity of incretin hormones, which increase insulin secretion and decrease glucagon secretion, particularly after meals, thereby improving glycaemic control.
2. Indications
- Type 2 Diabetes Mellitus (T2DM):
- As monotherapy in patients who cannot tolerate metformin or in whom metformin is contraindicated.
- As add-on therapy to other anti-diabetic medications (e.g., metformin, sulfonylureas, insulin) to improve glycaemic control.
3. Dosage
Adults:
- Standard Dose: 100 mg orally once daily, with or without food.
Renal Impairment:
- Mild impairment (eGFR ≥45 mL/min): No dose adjustment needed.
- Moderate impairment (eGFR ≥30 to <45 mL/min): 50 mg once daily.
- Severe impairment (eGFR <30 mL/min, including end-stage renal disease): 25 mg once daily.
Elderly:
- Same as adult dosing, but monitor renal function closely.
Children:
- Not approved for use in patients under 18 years of age.
4. Administration
- Take once daily at the same time each day.
- Can be taken with or without food.
5. Forms Available
- Tablets: 25 mg, 50 mg, 100 mg
6. Side Effects
6.1 Common Side Effects:
- Nasopharyngitis (common cold)
- Headache
- Upper respiratory tract infection
6.2 Less Common Side Effects:
- Nausea
- Diarrhoea
- Fatigue
6.3 Rare but Serious Side Effects:
- Pancreatitis (severe abdominal pain, nausea, vomiting)
- Severe allergic reactions (e.g., angioedema, rash)
- Joint pain (arthralgia)
- Heart failure (in patients with cardiovascular risk factors)
7. Warnings
- Pancreatitis: Monitor for symptoms of acute pancreatitis; discontinue if suspected.
- Heart Failure: Use cautiously in patients with a history of heart failure.
- Severe Hypersensitivity Reactions: Discontinue immediately if signs of severe allergic reactions occur.
- Renal Function: Regular monitoring is recommended, especially in patients with renal impairment.
8. Precautions
- Not recommended for use in type 1 diabetes or for the treatment of diabetic ketoacidosis.
- Avoid use in patients with severe hepatic impairment due to limited safety data.
- Use cautiously in patients with a history of pancreatitis or severe hypertriglyceridaemia.
9. Interactions
- Sulfonylureas or Insulin: Increased risk of hypoglycaemia when used in combination; dose adjustments may be required.
- CYP3A4 inhibitors (e.g., ketoconazole): May slightly increase sitagliptin levels, though no dose adjustment is typically needed.
- Digoxin: Sitagliptin may increase digoxin levels; monitor for toxicity.
10. Monitoring Parameters
- Glycaemic control (HbA1c, fasting blood glucose) periodically.
- Renal function (eGFR) at baseline and during therapy.
- Signs and symptoms of pancreatitis (e.g., severe abdominal pain).
- Monitor for signs of heart failure in at-risk patients.
11. Use in Children
- Safety and efficacy have not been established in patients under 18 years of age.
12. Use in Pregnancy
- Category B: Limited human data; use only if clearly needed and the benefits outweigh the risks.
13. Use in Elderly
- Safe for use in elderly patients at standard doses, but renal function should be monitored closely due to age-related decline in kidney function.
14. Use in Kidney Disease
- Dose adjustment is required based on the severity of renal impairment.
15. Use in Liver Disease
- Limited data in severe hepatic impairment; avoid use in such patients.
16. Patient Counselling Points
- Take sitagliptin as prescribed, once daily at the same time each day.
- Inform your doctor if you experience severe abdominal pain, which may indicate pancreatitis.
- Monitor blood sugar levels regularly as advised by your doctor.
- Avoid skipping doses; if you miss a dose, take it as soon as you remember, but do not double the dose.
- Maintain a healthy diet and exercise routine for optimal diabetes control.
17. Table of Brand Names, Manufacturer, and Prices in USD
Brand Name | Manufacturer | Strength/Dosage Form | Price (USD) |
---|---|---|---|
Januvia | Merck | 100 mg Tablet | $500 (30 tablets) |
Generic Sitagliptin | Various | 100 mg Tablet | $250 (30 tablets) |
18. 15 FAQs (Frequently Asked Questions)
1. What is Sitagliptin used for?
Sitagliptin is used to manage type 2 diabetes and improve blood sugar levels.
2. How does Sitagliptin work?
It inhibits DPP-4, prolonging the action of incretin hormones, which help regulate insulin and glucagon levels.
3. Can Sitagliptin cause hypoglycaemia?
Rarely when used alone, but the risk increases when combined with sulfonylureas or insulin.
4. Can Sitagliptin cause weight gain?
No, sitagliptin is weight-neutral, meaning it does not typically cause weight gain.
5. Is Sitagliptin safe for use in renal impairment?
Yes, but the dose must be adjusted based on kidney function.
6. Can Sitagliptin cause pancreatitis?
Yes, pancreatitis is a rare but serious side effect.
7. Can Sitagliptin be taken with metformin?
Yes, it is often combined with metformin for better glycaemic control.
8. Can Sitagliptin be used in type 1 diabetes?
No, it is only approved for type 2 diabetes.
9. How should Sitagliptin be taken?
Take once daily, with or without food, at the same time each day.
10. Does Sitagliptin require blood monitoring?
Yes, regular monitoring of blood sugar levels and kidney function is recommended.
11. Can Sitagliptin be used during pregnancy?
It should be used during pregnancy only if the potential benefits outweigh the risks.
12. What should I do if I miss a dose?
Take the missed dose as soon as you remember, but skip it if it’s close to the next dose.
13. Can Sitagliptin cause joint pain?
Yes, severe joint pain has been reported as a rare side effect.
14. Can Sitagliptin be combined with insulin?
Yes, but close monitoring is required to avoid hypoglycaemia.
15. How long does it take for Sitagliptin to work?
It may take several weeks to see significant improvements in blood sugar levels.