What is the half life of Amaryl?

Amaryl (glimepiride) is an oral diabetes medicine that helps control blood sugar levels. It has a half-life of 5-8 hours but is metabolized by CYP2C9 enzymes in the liver to form a major active metabolite, cyclohexyl hydroxymethyl derivative (M1). M1 also has a blood sugar lowering effect (approximately one-third of that of Amaryl) and a half-life of 3 to 6 hours. The combined half-life of Amaryl and its active metabolite M1 is approximately 8 to 14 hours. The duration of effect of one dose of Amaryl is approximately 24 hours.

The half-life of a drug is an estimate of the time it takes for the concentration or amount in the body of that drug to be reduced by exactly one half (50%). After four to five half-lives, 97% of a drug has cleared from the body, and the drug is no longer considered to be having an effect, although, for most drugs, actual noticeable effects would have worn off well before then. The symbol for half-life is T½.

In reality, the half-life of Amaryl varies from person to person, and even sometimes within the same person. The half-life of Amaryl can also be affected by dosage and several other factors including:

• Age
• Impaired kidney function
• Impaired liver function
• Interacting medications (particularly those that are metabolized by CYP2D6 enzymes or other medicines that lower blood sugar)
• Pre-existing conditions
• Regular dosing of Amaryl.

See our article Drug Half-life Explained for more general information about half-lives.