From the FDA Drug Label
The administration of isosorbide mononitrate extended-release tablets 120 mg (2 x 60 mg tablets every 24 hours for 7 days) produced a dose-proportional increase in C maxand AUC, without changes in T maxor the terminal half-life. In a multiple-dose study, the effect of age on the pharmacokinetic profile of isosorbide mononitrate extended-release tablets 60 mg and 120 mg (2 x 60 mg) was evaluated in subjects ≥45 years The results of that study indicate that there are no significant differences in any of the pharmacokinetic variables of ISMN between elderly (≥65 years) and younger individuals (45 to 64 years) for the isosorbide mononitrate extended-release tablets 60 mg dose The older group (65 to 74 years) showed 30% lower apparent oral clearance (Cl/F) following the higher dose, i.e., 120 mg, compared to the younger group (45 to 64 years); Cl/F was not different between the two groups following the 60 mg regimen. While Cl/F was independent of dose in the younger group, the older group showed slightly lower Cl/F following the 120 mg regimen compared to the 60 mg regimen. The following table summarizes key pharmacokinetic parameters of ISMN after single- and multiple-dose administration of ISMN as an oral solution or isosorbide mononitrate extended-release tablets:
The hold parameters for Imdur (isosorbide mononitrate extended-release tablets) are not explicitly stated in the provided drug label. However, based on the pharmacokinetic data, the following parameters can be considered:
- Dose: 30-240 mg
- Administration: once daily, taken early in the morning on arising
- Terminal half-life: approximately 5 hours
- Renal clearance: accounts for only about 4% of total body clearance
- Hepatic impairment: no significant differences in pharmacokinetic variables were observed in patients with liver cirrhosis
- Renal impairment: no significant differences in pharmacokinetic variables were observed in patients with chronic renal failure
- Age: no significant differences in pharmacokinetic variables were observed between elderly (≥65 years) and younger individuals (45 to 64 years) for the 60 mg dose, but the older group showed 30% lower apparent oral clearance (Cl/F) following the 120 mg dose.
- Food effects: concomitant food intake may decrease the rate (increase in T max) but not the extent (AUC) of absorption of ISMN 1
From the Research
Isosorbide mononitrate (Imdur) should be held if the patient's systolic blood pressure is less than 90 mmHg or if the patient is experiencing symptoms of hypotension such as dizziness, lightheadedness, or syncope. This medication is a nitrate that works by relaxing and widening blood vessels, which can significantly lower blood pressure. The typical hold parameter is SBP < 90 mmHg, but this may vary based on the patient's baseline blood pressure and clinical condition 2. If a dose is held, it's essential to monitor the patient's blood pressure and reassess before administering the next scheduled dose. The medication should be resumed once blood pressure returns to an acceptable range, typically SBP > 90-100 mmHg and the patient is asymptomatic. Some key points to consider when holding Imdur include:
- Monitoring blood pressure closely to avoid hypotension 3
- Assessing the patient's clinical condition and adjusting the hold parameter as needed 4
- Resuming the medication once the patient's blood pressure is stable and they are asymptomatic 2
- Instructing patients to report persistent symptoms to their healthcare provider 2 The rationale for these hold parameters is to prevent dangerous hypotension that could lead to inadequate organ perfusion, falls, or other adverse events 5.