Peripheral gangrene complicating beta-blockade

Propranolol use in PHACE syndrome with cervical and intracranial arterial anomalies: collective experience in 32 infants

The objective of this retrospective study of patients evaluated between July 2008 and October 2011 in seven pediatric dermatology centers was to combine collective clinical experience using oral propranolol therapy in 32 infants with PHACE syndrome (Posterior fossa [brain malformations present at birth], Hemangioma [usually covering a large area of the skin of the head or neck >5 cm]; Arterial lesions [abnormalities of the blood vessels in the neck or head]; Cardiac abnormalities or aortic coarctation [abnormalities of the heart or blood vessels that are attached to the heart]; Eye abnormalities) with cervical or intracranial arterial anomalies. Patients were given an average daily dose of oral propranolol of 1.8 mg/kg divided two or three times per day for an average duration of 12.3 months. The main outcome measure was adverse neurologic events. Seven (22%) patients were categorized as being at higher risk for stroke, defined on magnetic resonance imaging as severe, long-segment narrowing or nonvisualization of major cerebral or cervical vessels without anatomic evidence of collateral circulation, often in the presence of concomitant cardiovascular comorbidities. Only one patient developed a change in neurologic status during propranolol treatment: mild right hemiparesis that remained static and improved while propranolol was continued. An additional three patients had worsening hemangioma ulceration or tissue necrosis during therapy. This is the largest report thus far of patients with PHACE syndrome treated with propranolol. Although no catastrophic neurologic events occurred, serious complications, particularly severe ulcerations, were seen in a minority of patients, and given the sample size, we cannot exclude the possibility that propranolol could augment the risk of stroke in this population. We propose radiologic criteria that may prove useful in defining PHACE patients as being at high or standard risk for stroke. We continue to advise caution in using systemic beta-blockers, particularly for children with vascular anomalies at higher risk for stroke. Use of the lowest possible dosage, slow dosage titration, three times per day dosing to minimize abrupt changes in blood pressure, and close follow-up, including neurologic consultation as needed, are recommended.

The effects of acebutolol and metoprolol on walking distances and distal blood pressure in hypertensive patients with intermittent claudication

The effects of acebutolol (with intrinsic sympathomimetic activity (ISA] and metoprolol (without ISA) on arm blood pressure, ankle systolic blood pressure, claudication distances (CD) and maximal walking distances (MWD) were compared in patients with essential hypertension and intermittent claudication. Fourteen patients participated in a long-term, open, randomized cross-over study. After randomization the patients received either acebutolol, 200 mg b.i.d., or metoprolol, 100 mg b.i.d. After eight weeks the drugs were shifted and after another eight weeks they were withdrawn. Arm and ankle blood pressure, CD and MWD were determined before randomization and after 4, 8, 12 and 16 weeks, and again 4-6 weeks after withdrawal of the drugs. The arm blood pressure was reduced by 20/13 mmHg after acebutolol and by 22/21 mmHg after metoprolol. In spite of a significant decrease in arm blood pressure there were no significant changes in ankle blood pressure, CD or MWD after the two drugs. After withdrawal of the drugs and after the arm blood pressure had returned to the control value no significant changes were seen in CD, MWD or ankle blood pressure. It is concluded that beta-blockers have no deleterious effect on CD, MWD or ankle blood pressure in patients with hypertension and intermittent claudication. No effect of ISA was demonstrated.

Tips and tricks on outpatient initiation and uptitration of beta-blockade in heart failure

beta-blockade has a therapeutic role across the continuum of patients with heart failure (HF), with a demonstrated mortality benefit in stage II and III HF. Concerns regarding initiation and uptitration linger as patients with resting bradycardia, pulmonary, or vascular disease are often unnecessarily excluded from receiving therapy. We will review the risk data on beta-blockade and offer therapeutic strategies to help overcome residual barriers to the initiation and uptitration of this important therapy in patients with HF.

Beta-blocker underuse in secondary prevention of myocardial infarction

OBJECTIVE

To review the clinical benefits of beta-blockers as secondary prevention following a myocardial infarction (MI) and to address the reasons that clinicians are reluctant to use beta-blockers in specific patient populations.

DATA SOURCES

MEDLINE was searched for articles published from January 1966 to October 2002. Relevant studies were identified by systematic searches of the literature for all reported studies of associations between beta-blocker underuse and secondary prevention of MI. Additional studies were identified by a hand search of references of original or review articles.

STUDY SELECTION AND DATA EXTRACTION

English-language human studies were selected and analyzed.

DATA SYNTHESIS

Associations were observed in studies of beta-blocker use as secondary prevention of MI. A lower rate of beta-blocker treatment occurred in older patients and in patients with comorbid conditions such as diabetes, heart failure, chronic obstructive pulmonary disease, asthma, and peripheral arterial disease. In addition, underuse was attributed to the perception of high rates of adverse events associated with beta-blockers. beta-Blocker use as secondary prevention of an MI can lead to a 19-48% decrease in mortality and up to a 28% decrease in reinfarction rates. Nonetheless, beta-blockers are significantly underused in many patient populations due to concomitant disease states. Due to their normal physiologic deterioration, the elderly are at an increased risk of low cardiac output and bradycardia when given a beta-blocker; therefore, they should be started on a low dose that is then slowly titrated. In diabetic patients, beta-blockers can impair glucose control leading to hypoglycemia; therefore, post-MI diabetic patients must routinely monitor their blood glucose levels. In patients with decompensated heart failure, beta-blocker use can lead to further cardiac depression, but lower oral starting doses with slow titration can reduce this risk. beta-Blockers can induce bronchospasm in patients with chronic obstructive pulmonary disease or asthma, but cardioselective beta-blockers and appropriate use of medications such as albuterol can minimize these effects. Finally, in patients with peripheral arterial disease, with the exception of hypertensive patients with Reynaud's phenomenon, beta-blockers can be used safely. The only absolute contraindications to beta-blockers are severe bradycardia, preexisting sick sinus syndrome, second- and third-degree atrioventricular block, severe left ventricular dysfunction, active peripheral vascular disease with rest ischemia, or reactive airway disease so severe that airway support is required.

CONCLUSIONS

Overall, the cardiovascular benefits of beta-blockers as secondary prevention of MI significantly outweigh the risks associated with their use.

Pharmacological prevention of cardiac risk in claudicants with ischaemic heart disease

BACKGROUND

Claudicants rarely progress to critical limb ischaemia but have a threefold increase in mortality, mainly due to cardiac disease. Antithrombotic therapy, beta blockers, ACE inhibitors and statins have been shown to reduce mortality and cardiovascular morbidity in patients with ischaemic heart disease.

AIM

To investigate secondary pharmacological prevention of ischaemic heart disease in claudicants.

MATERIALS AND METHODS

We prospectively recorded comorbidity and drug treatment in 89 patients (67 men and 22 women) with a history of ischaemic heart disease recruited in a supervised exercise and lifestyle modification programme to improve claudication distance and prognosis.

RESULTS

Of the 89 cases, 40 had a history of angina only and 49 of myocardial infarction. Sixteen (18%) had diabetes, 47 (53%) had hypercholesterolaemia and 52 (58%) were hypertensive. Antithrombotic therapy was prescribed to 61 patients (68.5%), 64 (72%) with a history of myocardial infarction and 27 (67.5%) with angina only (p = 1). Beta-blockers were prescribed to 12 (13.5%) patients only, seven (15%) with a history of myocardial infarction and five (12.5%) with angina only (p = 1). Of the 47 patients with hypercholesterolaemia, 29 (62%) were on a statin.

CONCLUSION

Secondary pharmacological prevention of ischaemic heart disease in claudicants remains suboptimal, with only two thirds of patients receiving antithrombotic therapy and a small minority receiving beta blockers. Pharmacological prevention in claudicants should improve to reduce cardiac morbidity and mortality.

beta blockade and intermittent claudication: placebo controlled trial of atenolol and nifedipine and their combination

OBJECTIVE

To determine the effects of the beta 1 selective adrenoceptor blocker atenolol, the dihydropyridine calcium antagonist nifedipine, and the combination of atenolol plus nifedipine on objective and subjective measures of walking performance and foot temperature in patients with intermittent claudication.

DESIGN

Randomised controlled double blind four way crossover trial.

SETTING

Royal Hallamshire Hospital, Sheffield.

SUBJECTS

49 patients (40 men) aged 39-70 with chronic stable intermittent claudication.

INTERVENTIONS

Atenolol 50 mg twice daily; slow release nifedipine 20 mg twice daily; atenolol 50 mg plus slow release nifedipine 20 mg twice daily; placebo. Each treatment was given for four weeks with no washout interval between treatments.

MAIN OUTCOME MEASURES

Claudication and walking distances on treadmill; skin temperature of feet as measured by thermistor and probe; blood pressure before and after exercise; subjective assessments of walking difficulty and foot coldness with visual analogue scales.

RESULTS

Atenolol did not significantly alter claudication distance (mean change -6%; 95% confidence interval 1% to -13%), walking distance (-2%; 4% to -8%), or foot temperature. Nifedipine did not alter claudication distance (-4%; 3% to -11%), walking distance (-4%; 3% to -10%), or foot temperature. Atenolol plus nifedipine did not alter claudication distance but significantly reduced walking distance (-9%; -3% to -15% (p less than 0.003)) and skin temperature of the more affected foot (-1.1 degrees C; 0 to -2.2 degrees C (p = 0.05)). These effects on walking distance and foot temperature seemed unrelated to blood pressure changes.

CONCLUSIONS

There was no evidence of adverse or beneficial effects of atenolol or nifedipine, when given singly, on peripheral vascular disease. The combined treatment, however, affected walking ability and foot temperature adversely. This may have been due to beta blockade plus reduced vascular resistance, which might also explain the reported adverse effects of pindolol and labetalol on claudication.

Measurement and cardiovascular relevance of partial agonist activity (PAA) involving beta 1- and beta 2-adrenoceptors

In the normal heart the ratio of beta 1/beta 2-receptors in both atria and ventricles is about 75:25; in the failing heart the ratio is about 60:40. Stimulation of either beta 1- or beta 2-receptors results in a positive chronotropic and inotropic response. In the periphery, with the exception of lipolysis, renin release, control of intraocular pressure and intestinal relaxation, beta 2-related activity predominates. The nature of the beta 2-receptor is being unravelled and it has now been cloned. The beta-receptor antagonist is 'anchored' via disulfide bonding. Subsequent events involve the regulatory protein guanine nucleotide which couples the receptor to adenylate cyclase. beta-receptor density may by up- or down-regulated. beta-stimulation down-regulates (uncouples and internalizes or sequestrates) and beta-antagonism up-regulates beta-receptor numbers, but the functional implications of such changes are not always clear. A partial agonist occupies a receptor site and competitively inhibits the full agonist (e.g. noradrenaline). A partial agonist differs from a full agonist in that maximal response of a tissue is less. When background sympathetic activity is absent or very low a partial agonist will act as an agonist, e.g. increase heart rate, but when background tone is high the partial agonist will behave functionally as an antagonist, e.g. decrease heart rate. In animals partial agonist activity (PAA) can be assessed in many ways. In the catecholamine-depleted (reserpine or syrosingopine), vagotomized or pithed, intact animal beta-activity can be assessed via changes in heart rate, cardiac contractility and atrioventricular conduction. Isolated organs can also be used such as atria, papillary muscle, tracheal, mesenteric artery and uterine preparations. The choice of animal is important as marked species differences in response can occur. In man assessing PAA is difficult due to the presence of an intact sympathetic system: the problem can be overcome by autonomic blockade of constrictor and vagal reflexes with prazosin, clonidine and atropine but leaving the beta-receptor mediated responses unimpaired. beta 1- and beta 2-selective PAA can also be gauged via an increased sleeping heart rate (basal sympathetic tone) in the presence and absence of a beta 1- and beta 2-selective antagonist. beta 1-selective PAA can also cause an increase in resting systolic blood pressure, beta 2-selective PAA may be further assessed by a fall in DBP, increased blood flow, fall in peripheral resistance or increased finger tremor.(ABSTRACT TRUNCATED AT 400 WORDS)

Birth defects following maternal exposure to ergotamine, beta blockers, and caffeine

Ergotamine exposure during pregnancy has been suggested to cause birth defects which have a vascular disruptive aetiology. The present case provides additional support for the possible adverse fetal effects of exposure to ergotamine, caffeine, and propranolol during the first four months of pregnancy. At birth the infant showed evidence of early arrested cerebral maturation and paraplegia. The nature of these defects suggests a primary vascular disruptive aetiology. We hypothesise that ergotamine, acting either alone or in synergy with propranolol and caffeine, produced fetal vasoconstriction resulting in tissue ischaemia and subsequent malformation. This case raises the possibility that fetal malformation may result from concomitant use of multiple vasoconstrictive agents during pregnancy.

Placebo-controlled comparison of captopril, atenolol, labetalol, and pindolol in hypertension complicated by intermittent claudication

In a six month placebo-controlled cross-over trial twenty patients with hypertension and peripheral arterial disease were randomised to captopril 25 mg twice daily, atenolol 100 mg once daily, labetalol 200 mg twice daily, or pindolol 10 mg twice daily for one month. Although all treatments were equally effective at lowering blood pressure, pain-free and maximum walking distances on a treadmill were decreased by atenolol, labetalol, and pindolol, but not by captopril. Post-exercise calf blood flow availability was impaired by atenolol, labetalol, and pindolol, but not by captopril. Despite ancillary characteristics of cardioselectivity, intrinsic sympathomimetic activity, or combination with alpha-blockade, beta-blockers seem to impair the lower limb circulation in such patients, whereas captopril seems to preserve it, possibly by maintaining the collateral blood supply.

The effects of propranolol and metoprolol on skin blood flow in diabetic patients

The effect of 2 weeks treatment with propranolol or metoprolol on skin blood flow (SBF) at rest was examined in 12 diabetic patients with essential hypertension in whom gross large vessel disease had been excluded. Neither drug significantly altered resting skin blood flow. However we cannot exclude an important difference between the two beta-adrenoceptor blockers because of the great variability of SBF within subjects. A larger study and/or more accurate methods of measuring SBF are needed to determine if beta 1-selective adrenoceptor antagonists differ from non-selective beta-adrenoceptor blockers with respect to skin blood flow.

Different effects of beta-1-adrenergic blocking agents with ISA or without ISA on peripheral blood flow

Until recently beta-adrenergic blocking agents were considered contraindicated in peripheral arterial occlusive disease (PAOD). However, in recent years several studies have failed to show negative effects on peripheral blood flow. It was the aim of this study to compare the effects of celiprolol, a beta-1-adrenergic blocking agent with intrinsic sympathomimetic activity (ISA), and of metoprolol, a beta-1-adrenergic blocking agent without ISA, on peripheral blood flow of patients with and without PAOD. In an acute trial 24 patients (group I: 12 patients with PAOD stage I and II; group II: 12 patients without PAOD received a single dose of 200 mg celiprolol or 200 mg metoprolol in a double-blind crossover design. Celiprolol induced no significant changes in calf and skin blood flow at rest or during reactive hyperemia. Basal vascular resistance (BVR) and minimal vascular resistance (MVR) were not affected. Metoprolol, however, significantly reduced muscle blood flow and increased BVR in both groups. Subsequently the patients were treated in a randomized double-blind design with a daily dose of 200 mg celiprolol or metoprolol for three weeks. In long-term treatment skin and muscle blood flow at rest and during reactive hyperemia, BVR, and MVR were not affected by celiprolol. Metoprolol significantly lowered calf blood flow at rest in patients with PAOD; other parameters remained unchanged. In patients without PAOD, metoprolol caused a significant decrease of calf blood flow at rest and an increase of BVR. Calf blood flow during reactive hyperemia, as well as skin blood flow at rest and during reactive hyperemia, showed no significant changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of beta-adrenergic blockers on the peripheral circulation in patients with peripheral vascular disease

Beta-Adrenergic blockers have not been widely used in patients with peripheral vascular disease because these drugs have been reported to worsen the symptoms of intermittent claudication. To test this assumption we studied the effects of a beta 1-selective and a nonselective beta-adrenergic blocker on postexercise calf blood flow and symptoms of claudication in 19 patients with mild-to-moderate peripheral vascular disease. Subjects received placebo for 3 weeks, and then were randomized to 120 mg/day propranolol or 150 mg/day metoprolol with the use of a crossover design. Blood flow in the calf was measured by strain-gauge plethysmography at rest and immediately after exercise on a bicycle ergometer at a low and a high workload. The symptoms of claudication were monitored during bicycle exercise and by patient diaries maintained between visits. Maximal exercise heart rate was reduced an equivalent amount by metoprolol (19 beats/min) and propranolol (16 beats/min). Mean arterial pressure was reduced by propranolol at rest and by both drugs with exercise. Calf blood flow was not affected by either drug compared with placebo at rest or at either workload. In addition, the symptoms of claudication were not worsened by either drug. We conclude that despite evidence of beta 1-adrenergic blockade and a lowering of arterial pressure, neither beta-adrenergic blocker adversely affected the peripheral circulation.

Walking capacity of patients with intermittent claudication during chronic antihypertensive treatment with metoprolol and methyldopa

In a placebo-controlled double-blind crossover trial, the effect of a 3-week course of treatment with metoprolol (100-200 mg daily) and methyldopa (500-1000 mg daily) on walking capacity on a treadmill with increasing work load was studied in 14 hypertensive patients with intermittent claudication. The walking capacity was not affected by the antihypertensive treatment.

The effect of withdrawal of beta-adrenergic blockade on intermittent claudication

Twenty-eight patients with intermittent claudication were studied before and one month after withdrawal of treatment with beta-adrenergic blocking drugs for hypertension, coronary heart disease or both. Heart rate, blood pressure, ankle/arm systolic blood pressure ratio and ankle pulse volume recording (PVR) at rest and after treadmill exercise were recorded, as well as walking distance, time of recovery from subjective symptoms, restitution time of pressure ratio and PVR. A control group of 14 patients, whose beta-adrenergic blocking drugs were not withdrawn, was also included. The result can be summarized as showing that withdrawal of beta-blockade was not demonstrably advantageous in patients with intermittent claudication. Significant improvement was observed only during the first month of the trial, a change which was independent of withdrawal of beta-blockade. The relief of subjective symptoms after exercise occurred significantly faster after withdrawal of nonselective beta-blockade. Otherwise, there was no difference between nonselective and cardioselective beta-adrenergic blocking drugs.

Effect of propranolol on the tone of collateral arteries in patients with occlusion of the superficial femoral artery

The effect of administration of 0.5 mg propranolol into the femoral artery in eight patients with lower limb ischaemia and superficial femoral artery occlusion on collateral arterial resistance was studied in supine and tilted head-up position. Mean blood pressures were recorded directly from the femoral and popliteal artery and femoral blood flow was measured by an indicator dilution technique. After beta-receptor blockade in the supine position the collateral arterial resistance increased by 7 +/- 2%, femoral blood flow decreased 10 +/- 4%, and popliteal artery pressure increased by 4 mmHg (8 +/- 3%). During head-up tilt there was no change in femoral blood flow and collateral arterial resistance after propranolol. The peripheral vasoconstrictor effect of propranolol, therefore, seems not to be harmful to patients with vascular disease.

Effect of long-term beta-adrenergic-blockade on calf blood flow in hypertensive patients

The effect of a four-week treatment with propranolol and metoprolol on blood pressure and regional haemodynamics of the lower extremity at rest, after exercise and during reactive hyperaemia was studied in 34 patients with essential hypertension, but without peripheral arterial disease, in a randomized placebo-controlled trial. No significant difference in side-effects recorded during the trial was observed between these two drugs. Treatment with beta-adrenergic blocking drugs reduced systemic blood pressure. Calf blood flow during vasodilatation was also decreased. The most marked changes were observed during reactive hyperaemia; mean calf blood flow was reduced from about 250 ml/min/litre of tissue to 200 ml/min/litre of tissue (P less than 0.01) by propranolol and to 214 ml/min/litre of tissue (P less than 0.01) by metoprolol. Both drugs caused a significant increase in peripheral resistance above the initial level during reactive hyperaemia (P less than 0.05). No significant difference in peripheral resistance was observed, however, when the active drugs were compared with the placebo. There was no difference between propranolol and metoprolol in any of the parameters. Thus, the flow reduction can mainly be attributed to the diminished perfusion pressure due to the decreased cardiac output caused by beta-blockade of the heart.

The acute and chronic effect of oxprenolol and propranolol on peripheral blood flow in hypertensive patients

1 The effects of oxprenolol and propranolol on peripheral blood flow were compared in patients with mild and moderate essential hypertension. 2 In an acute double-blind crossover study in which eight patients participated there was a significant reduction in resting forearm blood flow (RFBF) 2 h after 80 mg propranolol (mean +/- s.e. mean) (-0.87 +/- 0.13 microliter min-1 100 g-1) and after 80 mg oxprenolol (-0.30 +/- 0.12) but not after placebo. This reduction was significantly greater after propranolol (P = 0.022). 3 Seven patients continued into a double-blind crossover study comparing the above dose of the two drugs twice a day. On both the beta-adrenoceptor blockers there was a significant reduction in blood pressure after 2 weeks of treatment and also a significant reduction in RFBF. 4 After 6 weeks treatment with propranolol the reduction in RFBF persisted and was significantly less (P = 0.04) than after 6 weeks treatment of oxprenolol, at which time RFBF was back to control. 5 There were no consistent changes in skin temperature. 6 Neither propranolol nor oxprenolol should be used in patients with severe peripheral vascular disease. 7 If beta-adrenoceptor blockade is necessary in patients with mild peripheral vascular disease oxprenolol should be used in preference to propranolol but should be prescribed with caution.

Lower extremity ischemia due to combined drug therapy for migraine

Three days after initiation of migraine headache therapy with ergotamine tartrate and propranolol, severe acute arterial insufficiency of the lower extremities developed in a 48-year-old woman who had been in general good health. Angiography revealed hypoplastic aortoiliac arteries, with tubular narrowing of the leg arteries. Lower extremity blood pressures rapidly returned to normal with a single intraarterial injection of 25 mg of tolazoline. Cases of peripheral ischemia due to either ergotamine or propranolol have been reported. Combined use of these two drugs may enhance the risk of acute arterial compromise.

Beta-adrenoceptor-blocking agents: are pharmacologic differences relevant?

beta-Adrenoceptor-blocking agents constitute a heterogeneous group of compounds. Membrane- stabilizing (quinidine-like) effects can be demonstrated pharmacologically with most compounds, but only at relatively high concentrations. There is no evidence to suggest that this property is of clinical relevance. Some compounds have a certain selectivity for receptors of the beta 1-type, whereas others possess beta-adrenoceptor stimulant activity (partial agonism). The clinical importance of these latter properties remains controversial. The selectivity for beta 1-adrenoceptors, which can be demonstrated pharmacologically for atenolol, metoprolol, and practolol, appears quite broad. Nevertheless a clear advantage over nonselective compounds with respect to their effects on lung function and vascular resistance in patients has not been established. There are two possible explanations. The first is that the doses used therapeutically may lie outside the selective range; the second is that most tissues appear to possess and mixed population of beta 1- and beta 2-adrenoceptors. According to our present understanding, even absolute specificity for a given subtype cannot provide organ or tissue specificity. Partial agonists provide a constant stimulation of beta-adrenoceptors while at the same time preventing access of catecholamines to the receptor they occupy. With some compounds (e.g., pindolol), stimulant activity may be sufficient to counterbalance the myocardial depression normally resulting from blockade of basal sympathetic tone. Heart rate and cardiac output are thus maintained within normal limits and compensatory increases in vasomotor tone (seen with antagonists lacking intrinsic activity) do not occur. Pindolol has been shown to dilate blood vessels at very low doses and to produce significant relaxation of isolated tracheal smooth muscle at concentrations within the range of therapeutic plasma levels found in humans. These effects may underly the relatively low incidence of bronchopulmonary and vascular side effects reported for this compound.

Beta-adrenergic blockade and peripheral vascular disease

Hypertension and ischaemic heart disease are common accompaniments of peripheral vascular disease, and are often treated with beta-blocking drugs. Previous reports, however, have suggested that these drugs may aggravate peripheral vascular disease. A study was designed to investigate this problem with claudication-distance and skin and muscle blood-flow studies (as determined by 133Xe clearance) as indices for assessment. In all 11 patients who presented with features of peripheral vascular disease and were found to be taking beta-blocking drugs, administration of the drug was stopped, blood pressure was controlled by other means, and the situation was reassessed four weeks later. There was a significant improvement in claudication distance and in resting and post-exercise muscle blood flow after withdrawal of the drug. This held for both cardioselective and nonselective beta-blockers. It is recommended that this group of drugs be avoided in the treatment of patients with peripheral vascular disease.

Effects of propranolol and metoprolol on the peripheral circulation

The effects of single doses of propranolol and metoprolol on skin temperature and skin and muscle blood flow were compared in 10 normal subjects and four patients with essential hypertension. In normal subjects the mean skin temperature fell by 1.30 +/- 0.62 degrees C 90 minutes after 80 mg propranolol and 0.15 +/- 0.05 degrees C after 100 mg metoprolol. Skin blood flow and resting muscle blood flow were not affected by metoprolol but fell significantly after propranolol. Both drugs reduced post-exercise muscle hyperaemia, propranolol by more than metoprolol. Similar changes were seen in the hypertensive patients. Propranolol should be used with care in patients with known vascular disease.