From the Guidelines
Glucagon has a rapid onset of action, typically beginning within 5-10 minutes after administration. When given intravenously, effects can be seen even faster, often within 1-3 minutes. For intramuscular or subcutaneous injections, which are more common in emergency settings, the onset takes slightly longer but is still relatively quick. The peak effect of glucagon occurs around 20-30 minutes after administration, and its duration of action is approximately 60-90 minutes. Glucagon works by stimulating glycogenolysis in the liver, which is the breakdown of stored glycogen into glucose that is then released into the bloodstream. This mechanism explains why glucagon is effective for treating severe hypoglycemia in diabetic patients, particularly when they are unconscious or unable to consume oral glucose. It's essential to note that glucagon's effectiveness depends on adequate glycogen stores in the liver, so it may be less effective in patients who are malnourished, have liver disease, or have been fasting for extended periods 1.
Some key points to consider when administering glucagon include:
- Ensuring that caregivers, school personnel, or family members providing support to individuals with diabetes know where the glucagon is and when and how to administer it 1
- Recognizing the signs and symptoms of hypoglycemia, including shakiness, irritability, confusion, tachycardia, and hunger, and taking prompt action to treat it 1
- Understanding that glucagon is indicated for the treatment of hypoglycemia in patients unable or unwilling to consume carbohydrates by mouth 1
- Being aware that hypoglycemia unawareness or one or more episodes of level 3 hypoglycemia should trigger hypoglycemia avoidance education and reevaluation and adjustment of the treatment plan to decrease hypoglycemia 1
From the FDA Drug Label
Table 2: Dose and Pharmacodynamic properties of Glucagon for Injection as a Diagnostic Aid Dose Route of administration Time of onset of action Approximate duration of effect 0.25 to 0. 5 mg Intravenous 1 minute 9 to 17 minutes 1 mg Intramuscular 8 to 10 minutes 12 to 27 minutes 2 mg Intravenous 1 minute 22 to 25 minutes 2 mg Intramuscular 4 to 7 minutes 21 to 32 minutes
The onset of action for glucagon is:
- 1 minute for intravenous administration of 0.25 to 0.5 mg and 2 mg
- 8 to 10 minutes for intramuscular administration of 1 mg
- 4 to 7 minutes for intramuscular administration of 2 mg [2] [3]
From the Research
Onset of Action for Glucagon
- The onset of action for glucagon can vary depending on the route of administration.
- For intravenous (i.v.) administration, the onset of action is rapid, with plasma glucagon levels rising significantly within 15 minutes 4.
- For intramuscular (i.m.) administration, the onset of action is slower, with recovery of normal conscious level taking around 9 minutes 5 to 8-21 minutes 6.
- For subcutaneous (s.c.) administration, the onset of action is similar to i.m. administration, with no significant difference in blood glucose behavior 4.
- Intranasal (IN) glucagon has also been shown to be effective in resolving hypoglycemia, with a similar onset of action to i.m./s.c. glucagon 7.
- The exact onset of action for glucagon can vary depending on the individual and the specific circumstances of administration, but overall, i.v. administration appears to have the fastest onset of action, followed by i.m./s.c. and IN administration.