Plasma Half-Life of Hawthorn Root
The plasma half-life of Hawthorn (Crataegus) root is not well established in scientific literature, but based on available evidence, it appears to have a relatively short half-life of approximately 2-4 hours.
Pharmacokinetic Properties of Hawthorn
Hawthorn extract contains several bioactive compounds, primarily:
- Flavonoids (including epicatechin)
- Oligomeric procyanidins
- Cardiac glycosides
Absorption and Distribution
- Hawthorn compounds are absorbed through the gastrointestinal tract
- Peak effects of certain hawthorn components have been observed at approximately 20 minutes post-administration with effects lasting up to 4 hours 1
- The bioactive compounds in hawthorn appear to have varying bioavailability rates
Metabolism and Excretion
- Hawthorn compounds undergo hepatic metabolism
- Some components may interact with cytochrome P450 enzymes
- Elimination appears to be primarily through renal excretion
Clinical Implications
Cardiovascular Effects
- Hawthorn has demonstrated positive inotropic effects
- It can improve coronary blood flow
- May have antiarrhythmic properties 2
- Can cause bradycardia in higher doses due to cardiac glycoside activity 3
Potential Drug Interactions
- May interact with vasodilating medications
- Potential to potentiate or inhibit actions of drugs used for heart failure, hypertension, and arrhythmias 2
- Particular caution is warranted when used with other cardiac medications
Bleeding Risk
- Evidence suggests hawthorn may increase bleeding risk
- A prospective trial found significantly more bleeding events requiring return to the operating room in patients taking hawthorn extract compared to those who never received it (10% vs 1%, p=0.03) 1
Dosing Considerations
The recommended daily dose of hawthorn extract is 160-900 mg of water-ethanol extract of leaves or flowers (equivalent to 30-169 mg of epicatechin or 3.5-19.8 mg of flavonoids), typically administered in two or three divided doses 2. This dosing schedule aligns with the relatively short half-life of the active compounds.
Safety Profile
At therapeutic dosages, hawthorn may cause:
- Mild rash
- Headache
- Sweating
- Dizziness
- Palpitations
- Sleepiness
- Gastrointestinal symptoms 2
More severe cases may present with:
- Significant bradycardia
- Myalgias
- Detectable plasma digoxin concentrations (due to cross-reactivity with cardiac glycosides) 3
Clinical Monitoring
When administering hawthorn preparations, monitoring should include:
- Heart rate and blood pressure
- Signs of bleeding, particularly in patients undergoing surgery
- Potential drug interactions with concurrent medications
- Symptoms of toxicity including myalgias and bradycardia
The short half-life of hawthorn compounds suggests that dosing multiple times per day may be necessary to maintain therapeutic effects, and that adverse effects would likely resolve within 24 hours of discontinuation.