Onset of Action for Procardia XL (Nifedipine)
Procardia XL (nifedipine extended-release) begins to work within 2.5-5 hours after ingestion, with a second small peak occurring at approximately 6-12 hours post-dose. 1
Pharmacokinetic Profile
- Nifedipine is completely absorbed after oral administration, with the extended-release formulation (Procardia XL) having a bioavailability of 84%-89% relative to immediate-release tablets 1
- Under fasting conditions, plasma concentrations peak at about 2.5-5 hours after ingestion of Procardia XL 1
- A second small peak or shoulder is typically evident at approximately 6-12 hours post-dose 1
- The elimination half-life of nifedipine administered as extended-release tablets is approximately 7 hours, compared to the 2-hour elimination half-life of immediate-release nifedipine 1
Clinical Considerations
- Procardia XL's once-daily dosing results in decreased fluctuations in plasma concentration compared to three-times-daily dosing with immediate-release nifedipine capsules 1
- Food intake can affect the absorption profile - when taken immediately after a high-fat meal, there is an average increase of 60% in peak plasma nifedipine concentration and a prolongation in time to peak concentration 1
- The extended-release formulation maintains therapeutic blood pressure control over a full 24-hour period, as demonstrated in ambulatory blood pressure monitoring studies 2
Formulation Comparisons
- Different extended-release formulations of nifedipine (such as Adalat CC and Procardia XL) have been shown to be equally effective at controlling blood pressure over a 24-hour period 2
- The OROS (Osmotic Release Oral System) technology used in Procardia XL controls the rate of drug release for a predetermined time, providing constant delivery profiles 3
Clinical Effects Timeline
- For hypertension management, blood pressure reduction begins as the drug reaches therapeutic plasma levels (within 2.5-5 hours) 1, 2
- Full therapeutic effect may take several days of consistent dosing to achieve steady-state plasma levels 4
- For calcium channel blockers like nifedipine, the European Society of Cardiology notes that the onset of action is typically 5-15 minutes for immediate-release forms, but the extended-release formulation (Procardia XL) has a more gradual onset 5
Safety Considerations
- The extended-release formulation helps minimize adverse effects associated with rapid increases in plasma concentration 3
- Immediate-release nifedipine should not be administered to patients with acute coronary syndromes in the absence of beta-blocker therapy due to risk of adverse cardiovascular events 6
- The insoluble tablet shell of Procardia XL may be visible in stool after the medication has been absorbed 3, 7
Understanding the onset of action of Procardia XL is important for patient education and appropriate clinical use in conditions like hypertension and angina, where the extended-release formulation provides more consistent blood levels throughout the day compared to immediate-release formulations.