Hawthorn: Dosage. Interactions. Practice Points

Dosage Range • Infusion of dried herb: 0.2-2 g three times daily. • Tincture of leaf (1:5): 3.5-17.5 mL/day. • Fluid extract (1:2): 3-6 mL/day. • Herpes simplex outbreak: 4 mL three times daily at the first sign of infection for a maximum of 2 days. Toxicity No target toxicity to 100-fold the human dose of the WS 1442 extract is defined. This is in contrast to inotropic drugs, such as digoxin, which generally have a low therapeutic index. Adverse Reactions Sweating, nausea, fatigue and a rash on the hands have been reported in one clinical trial using a commercial preparation containing 30 mg hawthorn extract standardised to 1 mg procyanidins. Headache, sweating, dizziness, palpitations, sleepiness, agitation, and gastrointestinal symptoms have also been reported. Significant Interactions Controlled studies are not available; therefore, interactions are based on evidence of activity and are largely theoretical and speculative. CARDIAC GLYCOSIDES Hawthorn may theoretically potentiate the effects of cardiac glycosides, as both in vitro and in vivo studies indicate that it has positive inotropic activity. Furthermore, the flavonoid components of hawthorn may also affect P-glycoprotein function Read more […]

Hawthorn: Background. Actions

Historical Note The name ‘hawthorn’ comes from ‘hedgethorn’, after its use as a living fence in much of Europe. Dioscorides and Paracelsus praised hawthorn for its heart-strengthening properties and it is also known in TCM. It has since been shown to have many different positive effects on the heart and is a popular prescription medicine in Germany for heart failure. Common Name Hawthorn Other Names Aubepine, bianco spino, crataegi (azarolus, flos, folium, folium cum flore [flowering top], fructus [berry], nigra, pentagyna, sinaica boiss), English hawthorn, Chinese hawthorn, fructus oxyacanthae, fructus spinae albae, hagedorn, hedgethorn, maybush, maythorn, meidorn, oneseed hawthorn, shanzha, weissdorn, whitehorn Botanical Name / Family Crataegus laevigata, Crataegus cuneata, Crataegus oxyacantha, Crataegus monogyna, Crataegus pinnatifida (family Rosaceae [Rose]) Plant Parts Used Extracts of the leaf and flower are most commonly used, although the fruit (berries) may also be used. Chemical Components Leaves and flowers contain about 1% flavonoids, such as rutin, quercitin, vitexin, hyperisise, 1-3% oligomeric procyanidins including catechin and epicatechin, triterpenes, sterols, polyphenols, coumarins, tannins. Read more […]

β-ADRENOCEPTOR ANTAGONISTS

β-ADRENOCEPTOR ANTAGONISTS (also known as β-adrenergic receptor blocking drugs, β-adrenoceptor blocking drugs or beta-blockers) are drugs that inhibit certain actions of the sympathetic nervous system by blocking the action of adrenaline and noradrenaline (catecholamine mediators acting predominantly as hormone or neurotransmitter respectively). Among other actions, β-adrenoceptors have cardiac stimulant actions, they dilate certain blood vessels, suppress motility within the gastrointestinal tract, stimulate certain aspects of metabolism causing an increase in glucose and free fatty acids in the blood. These actions, in concert with those of the α-adrenoceptors, help prepare the body for emergency action. However, in disease, some of these effects may be inappropriate, exaggerated and detrimental to health, so β-blockers may be used to restore the balance. Thus β-blockers are used to lower blood pressure when it is abnormally raised in cardiovascular disease (see ANTIHYPERTENSIVE AGENTS): to correct certain heartbeat irregularities and tachycardias (see ANTIARRHYTHMICS); to prevent the pain of angina pectoris during exercise by limiting cardiac stimulation (see ANTIANGINALS)’, to treat myocardial infarction, Read more […]

ADENOSINE RECEPTOR AGONISTS

ADENOSINE RECEPTOR AGONISTS act extra cellularly at receptors variously known as adenosine receptors, P1 purine receptors, P1 receptors, P1 purinoceptors, or nucleoside receptors. Adenosine receptors have a wide range of mainly inhibitory actions in the body, including cardiac slowing, a fall in blood pressure, dilation of bloqd vessels, inhibition of platelet aggregation, inhibition of intestinal movements and actions within the central nervous system. Subtypes of adenosine receptors exist — A1, A2 and A3 — which have differential sensitivities to adenosine nucleoside analogues, including 2-methylthio-AMP, 2-thioadenosine, DPMA, IB-MECA, NECA, CPA, CCPA and DPCPX. These receptors, and subtypes within A2, have all been cloned. They have structures typical of the seven-transmembrane G-protein-coupled superfamily of receptors, but have amongst the shortest sequences known (A3 has only 318 amino acids), and a lack of sequence similarity with any other receptors appears to put them in a class of their own. Adenosine receptors are not sensitive to nucleotides such as ADP (adenosine diphosphate) and ATP (adenosine triphosphate), which instead act as P2 receptor agonists that are nucleotide-preferring (see P2 receptor Read more […]

ANTIARRHYTHMIC AGENTS

ANTIARRHYTHMIC AGENTS (antidysrhythmic agents) are used to treat a number of heart conditions characterized by irregularities of heart beat. They have been classified under the Vaughan Williams Scheme, though not all clinically used agents neatly fit these classes. Class I (which has a number of subtypes) is mainly used to treat atrial and ventricular tachycardias, and contains a number of SODIUM-CHANNEL BLOCKERS, e.g. disopyramide, flecainide, lignocaine, procainamide and quinidine. Class II, which is valuable for stress-induced tachycardias, contains β-ADRENOCEPTOR ANTAGONISTS, e.g. metoprolol, propranolol. Class III, which is used for certain tachycardia syndromes, includes amiodarone (whose mechanism of action is not clear), POTASSIUM-CHANNEL BLOCKERS and the atypical β-blocker sotalol. Class IV is used for atrial tachyarrhythmias and contains certain CALCIUM-CHANNEL BLOCKERS, e.g. diltiazem and verapamil. In addition to drugs in these classes, others may be used for certain arrhythmias. Digoxin may be used for treatment of atrial fibrillation, adrenaline for asystolic cardiac arrest, atropine for sinus bradycardia, methacholine (rarely) for supraventricular tachycardia, magnesium salts for ventricular Read more […]

Magnesium: Interactions. Contraindications. Pregnancy Use

Adverse Reactions The most common adverse effects of oral supplements are diarrhea (18.6%) and gastric irritation (4.7%). Typically, doses above 350 mg/day (elemental) may be associated with adverse effects. Significant Interactions The interactions included in this section are relevant for oral supplementation and do not refer to other administration routes, although there may be an overlap. AMINOGLYCOSIDES (E.G. GENTAMYCIN) Drug may reduce absorption of Mg — monitor for signs and symptoms of Mg deficiency, as increased Mg intake may be required with long-term therapy. CALCIUM-CHANNEL BLOCKERS Magnesium may enhance the hypotensive effect of calcium-channel blockers: monitor patients and their drug requirements — possible beneficial interaction. FLUOROQUINOLONES Magnesium may decrease absorption of fluoroquinolone antibiotics — separate doses by at least 2 hours before or 4 hours after oral Mg. LOOP DIURETICS AND THIAZIDE DIURETICS Increased Mg intake may be required with long-term therapy because these drugs increase Mg loss — monitor Mg efficacy and status with long-term drug use. TETRACYCLINE ANTIBIOTICS Tetracyclines form insoluble complexes with Mg, thereby reducing absorption of both — separate Read more […]