Current treatment options for fissure-in-ano

BACKGROUND

Fissure-in-ano is a painful condition that affects a sizable majority of the population. Selecting a method of treating the condition that could achieve optimal clinical results and the least pain and inconvenience to the patient has always posed a challenge to the surgeons. This led to the innovation of a number of surgical and pharmacological methods that relax the anal muscle. While acute fissures could be managed with medical therapy alone, chronic fissures do need some form of manipulation to relieve internal sphincter spasm.

MATERIALS AND METHODS

The present study discusses various techniques advocated for the treatment of acute and chronic fissure-in-ano. It also elaborates on the advantages and deficiencies of each.

DISCUSSION

Despite the initial success with pharmacological agents in the treatment of patients with chronic anal fissures, a growing concern is developing about their use. Increasing incidence of adverse effects and decreasing long-term efficacy have been the major drawbacks.

CONCLUSION

Surgery still remains the preferred option which should be offered to patients with relapse or therapeutic failure with prior pharmacological treatment. Nevertheless, the patient should be informed about the pros and cons of each mode of treatment with details of cure rates and possible complications.

Paced respiratory sinus arrhythmia as an index of cardiac parasympathetic tone during varying behavioral tasks

This study addresses a number of unresolved issues regarding the employment of respiratory sinus arrhythmia as an index of tonic parasympathetic cardiac control in psychophysiological investigations. These questions include the following: (1) Does respiratory sinus arrhythmia reflect cardiac vagal tone under conditions in which alterations in parasympathetic control are expected to be mild to moderate? (2) Are variations in human respiratory sinus arrhythmia that occur in response to varying behavioral demands independent of beta-adrenergic effects on the heart? (3) To what extent do typical experimental tasks apparently affect tonic cardiac vagal control? Twelve healthy male subjects were administered a joint alpha- and beta-adrenoreceptor pharmacological blocker on one day and a placebo on another (balanced across subjects). On both days, respiratory sinus arrhythmia and heart period were monitored during a number of different experimental tasks while subjects continuously paced their respiration. Results indicated that respiratory sinus arrhythmia, under controlled respiratory conditions, is uninfluenced by variations in sympathetic activity, and provides a reasonably sensitive index of cardiac vagal tone, even when alterations in parasympathetic tone are not large. Furthermore, our findings suggest that cardiac vagal tone is responsive to varying behavioral demands and may interact in different ways with beta-adrenergic mechanisms.

Double-blind study comparing indoramin and propranolol in the treatment of black patients with hypertension

A 20-week double-blind randomised study of 50 black hypertensive patients was designed to compare the efficacy and safety of indoramin (Baratol; Wyeth/Ayerst) and propranolol in patients who did not respond to diuretic therapy alone. Indoramin (initial dose 50 mg/d) or propranolol (initial dose 80 mg/d) was added to the regimen of patients whose supine diastolic blood pressure (SDBP) remained elevated at 100- 200 mmHg after 2 weeks' treatment with a combination diuretic tablet (hydrochlorothiazide 50 mg plus amiloride HCl 5 mg). Supine systolic blood pressure (SSBP) and SDBP of all patients was successfully controlled (SDBP lowered to less than 95 mmHg) by daily doses that did not exceed 100 mg of indoramin or 160 mg of propranolol; over 90% of patients in each group achieved control with lower doses, i.e. 50-75 mg of indoramin or 80-120 mg of propranolol. Although heart rate decreased from baseline values by approximately 9/min with both agents, the decreases were not significantly different between the treatment groups, and neither agent caused orthostatic hypotension. There were no statistically significant differences between the groups in the types or frequency of side-effects. Indoramin is well tolerated and is as effective as propranolol in black patients with essential hypertension who are not controlled by a thiazide diuretic alone.

Pharmacokinetics of indoramin and its 6-hydroxylated metabolite after repeated oral dosing

The pharmacokinetics of indoramin and its active 6-hydroxylated metabolite have been studied in healthy male volunteers after repeated oral dosing with 37.5 mg twice daily for 2 weeks. Plasma concentrations of indoramin accumulated, on average, three to four-fold above those anticipated on the basis of the kinetics after the first dose, though steady state was achieved by the end of the first week and no further increase was observed after 2 weeks. The degree of accumulation was consistent between subjects, with a highly significant (p less than 0.001) correlation between the concentration 2 h after a single dose and the average steady-state concentration. Possible explanations for the accumulation of indoramin are discussed. Plasma concentrations of 6-hydroxyindoramin, in contrast, did not accumulate on multiple dosing. At steady state, concentrations of the metabolite, as represented by the AUC0-8h, were approximately 30-40 per cent of those of the unchanged drug. Since the two compounds are approximately equipotent the metabolite may accounts for 25 per cent of the hypotensive activity of indoramin during a typical clinical regime of 37.5 mg twice daily.

Intra- and inter-subject variation in the pharmacokinetics of indoramin and its 6-hydroxylated metabolite

Intra- and inter-subject variation in the kinetics of indoramin and its active metabolite 6-hydroxyindoramin have been studied in 5 young, healthy, male volunteers administered a single oral dose of the drug on 5 separate occasions. Inter-subject variation represented the main source of variability in indoramin plasma concentrations with, for example, the between-subjects sum of squares (a measure of the contribution to the total variability) representing around 97% of the total sum of squares for Cmax and AUC (0-24). Intra-subject and inter-subject coefficients of variation (C.V.s) were circa 20% and 100% respectively for both these parameters. Variability in 6-hydroxyindoramin concentrations was much lower and was approximately equally derived from intra- and inter-subject variation, with the C.V.s being approximately 44% for both Cmax and AUC (0-24). The results imply that the kinetic behaviour of indoramin within an individual will prove relatively consistent, despite widespread inter-subject variation, once an appropriate dosage regime has been established.

Hemodynamic responses to indoramin at rest and during exercise in congestive heart failure

Twenty patients with congestive heart failure underwent hemodynamic studies before and over 10 hours after the administration of 25, 50, and 75 mg of indoramin, an alpha 1-adrenergic antagonist. Hemodynamic studies were repeated during exercise after the administration of the optimal dose of indoramin. The drug reduced resting and exercise pulmonary capillary wedge pressure, right atrial pressure, systemic blood pressure and vascular resistance, and pulmonary artery pressure and vascular resistance. Resting and exercise stroke volume and cardiac output rose in response to the fall in vascular resistances. Heart rate was not altered at rest or during exercise. The first dose of the alpha 1 blocker indoramin elicits a significant reduction in ventricular preload and afterload and augmentation of ventricular performance in patients with congestive heart failure.

Long-term indoramin therapy in congestive heart failure: a double-blind, randomized, parallel placebo-controlled trial

Twenty-one patients with moderately severe congestive heart failure participated in a double-blind, randomized, parallel placebo-controlled trial designed to evaluate the effects of long-term (2 months) indoramin therapy on rest and exercise hemodynamics, exercise capacity and clinical status of patients with this clinical syndrome. The long-term administration of indoramin in patients (mean dose 50 mg every 12 hours) caused a mild reduction from baseline values in supine rest mean systemic blood pressure and, after dosing, elicited a significant reduction in systemic and pulmonary vascular resistances, pulmonary capillary wedge pressure and heart rate as well as a mild increase in stroke volume. Long-term indoramin therapy caused a small decrease, as compared with baseline exercise responses, in systemic and pulmonary vascular resistance and pulmonary capillary wedge pressure at submaximal levels of exercise. It did not alter hemodynamic variables at maximal exercise, exercise capacity or overall clinical status, compared with findings at baseline or with placebo.

Indoramin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in hypertension and related vascular, cardiovascular and airway diseases

Indoramin is a postsynaptic selective alpha 1-adrenoceptor antagonist used in the treatment of hypertension. In contrast to some other alpha-blockers, animal studies suggest that its blood pressure lowering effect results from relaxation of peripheral arterioles as a consequence of blockade of postsynaptic alpha 1-adrenoceptors. Furthermore, unlike some other alpha-blockers, this lowering of blood pressure is rarely associated with reflex tachycardia or postural hypotension. Therapeutic trials have shown indoramin to be effective in lowering blood pressure in all grades of hypertension: mild and moderate hypertension when used alone, but generally in combination with a thiazide diuretic, and in moderate to moderately severe hypertension when used in combination with a beta-blocker and diuretic. In a few small comparative studies, no significant difference was found in the blood pressure lowering effects between indoramin and methyldopa, propranolol and prazosin. Side effects were similar for indoramin, propranolol and methyldopa; however in the 1 comparative study with prazosin, prazosin produced a lower incidence of sedation. Indeed, the most common side effect with indoramin therapy has been sedation of a mild to moderate and/or transient nature, reported in about 19% of cases. Other side effects which have sometimes led to a withdrawal of indoramin treatment have been dry mouth, dizziness, and in males, failure of ejaculation; however, side effects may be reduced by starting therapy with smaller doses and titrating more gradually.

Investigation into the cardioregulatory properties of the alpha 1-adrenoceptor blocker indoramin

The cardioregulatory properties of the alpha 1-adrenoceptor blocker indoramin have been compared with those of prazosin in the anaesthetized rat. The effects of autonomic blockade on heart rate responses evoked by these two agents and their effects on blood pressure and heart rate after peripheral or central administration have been compared. Cumulative administration of indoramin (0.8-25.6 mg kg-1 i.v.) evoked significant decreases in arterial blood pressure and a concomitant bradycardia. Pithing or autonomic blockade, by pretreatment with a combination of practolol and bilateral vagotomy, prevented the bradycardia evoked by indoramin (0.8-3.2 mg kg-1 i.v.). Atropine sulphate pretreatment abolished the bradycardia until a cumulative dose of 25.6 mg kg-1(i.v.) of indoramin had been reached. Bilateral vagotomy, intravenous administration of atropine methylnitrate or practolol pretreatment attenuated the bradycardia. Prazosin (0.02-0.64 mg kg-1 i.v.) evoked a fall in arterial blood pressure of similar magnitude to that observed following indoramin. A bradycardia was evoked only at a relatively high dose (0.64 mg kg-1 i.v.). Intracisternal injection of indoramin or prazosin evoked bradycardia and hypotension at a dose which had no effect after intravenous injection (25 micrograms). Intracerebroventricular injection of indoramin (25 micrograms) had no significant effect on heart rate or blood pressure compared to control values, whereas prazosin (25 micrograms) evoked a significant tachycardia and hypotension. It is concluded that the bradycardia evoked by indoramin in the rat is not due to a direct action on the heart except possibly at high doses. Central alpha 1-adrenoceptor blockade, possibly in the brainstem region, results in a bradycardia and this may explain the lack of reflex tachycardia following the administration of indoramin.

The cardiovascular effects of centrally and peripherally administered indoramin in conscious rats

Indoramin has centrally mediated hypotensive effects in anesthetized animals. In the present study, the cardiovascular effect of central and peripheral indoramin was determined in conscious, freely moving rats. Animals were instrumented with femoral arterial and venous catheters and miniaturized pulsed-Doppler flow probes were placed on the superior mesenteric and renal arteries and lower abdominal aorta. Injection of indoramin (25-100 micrograms) in the lateral cerebroventricle produced an immediate (1.5 min) increase in arterial pressure which was accompanied by vasoconstriction in all three vascular beds. By 10 min all values had returned to control except for heart rate which was decreased. Vehicle alone or intravenous indoramin (100 micrograms) had no effect. In baroreceptor-denervated rats smaller effects were seen. Intravenous indoramin (3.0-13.5 mg/kg) produced dose-related decreases in arterial pressure, heart rate, and hindquarter vascular resistance. The 13.5 mg/kg dose blocked to a similar degree the cardiovascular effect produced by intravenous norepinephrine or stimulation of the paraventricular nucleus. These data suggest that indoramin is an effective peripheral alpha-adrenergic receptor antagonist but does not appear to be centrally active as a hypotensive agent.

Pharmacokinetics of oral indoramin in elderly and middle-aged female volunteers

Indoramin was administered as a single 50 mg oral tablet to 5 elderly (aged 68-71 years) and 6 middle-aged (aged 46-55 years) healthy female volunteers. The mean half life of indoramin in elderly subjects (14.7 +/- 4.8 h, mean +/- SEM) was statistically significantly longer than that seen in middle-aged subjects (5.1 +/- 1.0 h). The mean plasma concentrations of indoramin and mean area under the plasma concentration/time curve were also greater in elderly than in middle-aged subjects, although this did not achieve statistical significance. In many elderly patients, therefore, a reduction in dosage may be required due to the apparent reduction in clearance of indoramin. However, because of the wide inter-subject variability observed in the oral pharmacokinetics of indoramin, individual titration of indoramin dosage in all patients may be desirable.

Pharmacokinetics of intravenous indoramin in middle-aged male and female volunteers

The pharmacokinetics of indoramin (Baratol) have been studied in five male and five female healthy, middle-aged volunteers after intravenous administration (0.14 mg/kg). Elimination occurred in an apparently biexponential fashion with a mean elimination half-life of 4.0 h (+/- 0.25 SEM). The mean plasma clearance was 19.9 ml/min/kg (+/- 1.32 SEM) and the mean volume of distribution 7.4 l/kg (+/- 0.81 SEM). There were no significant differences in these parameters between male and female volunteers. Protein binding of indoramin ranged from 85.6% at 81 ng/ml to 72.2% at 129 micrograms/ml. Two classes of binding site were evident, with affinity constants of 6.85 X 10(4)M -1 and 4.30 X 10(3)M -1.

Indoramin as an antihypertensive agent in the treatment of essential hypertension. A multicentre trial

The efficacy of indoramin (Baratol; Wyeth) in combination with a thiazide diuretic was assessed in an open non-comparative trial. The dosage of indoramin was increased at 2-weekly intervals until control was obtained or until a maximum daily dosage of 150 mg was reached. Treatment was successful in 78% of patients and a significant reduction in diastolic blood pressure (DBP) was obtained in another 7%. In combination with a thiazide diuretic, indoramin, when individually titrated for each patient, reduced the DBP by an average of 20 mmHg. When taken with a thiazide diuretic, indoramin 75 mg/d or less controlled the DBP in 76% of all the patients. The effect of indoramin on the pulse rate was minimal. For all practical purposes, orthostatic hypotension did not occur. A number of patients presented with side-effects but these proved to be transient in a large percentage of cases.

Indoramin in the treatment of hypertension. A mini-review and update

The origins, preclinical development and clinical pharmacology of a new antihypertensive agent, indoramin (Baratol; Wyeth), are briefly reviewed. Indoramin is a competitive postsynaptic alpha-adrenoceptor antagonist with a myocardial membrane-stabilizing component of action. These features are believed to be responsible for its antihypertensive efficacy. They may also explain the absence of problems common to older alpha-blockers such as reflex tachycardia and postural hypotension. Clinical evaluation of a new agent such as indoramin in the management of hypertension is discussed in terms of efficacy, dosage regimen, tolerance, adverse effects, interactions, withdrawal syndrome, and long-term influence on the complications of high blood pressure.

Cardiovascular effects of indoramin in man--a dose ranging study

1 The effect of single and repeated oral doses of indoramin 25 mg, 50 mg, 100 mg and placebo on arterial pressure and heart rate supine, standing and following immersion of the hand in ice was studied in five normal volunteers.

2 Each study period lasted 4 days. Observations were made before and at 2 and 4 after drug administration on days 1 and 4. On days 2 and 3, the drugs were administered daily, but no observations were made.

3 Indoramin did not change arterial pressure or heart rate in the supine position.

4 Indoramin did not reduce the cold pressor response.

5 Indoramin 25 mg produced small reductions in arterial pressure in the standing position, with no change in heart rate.

6 Indoramin 50 mg reduced systolic arterial pressure in the standing position on day 1 from 106.4 ± 2.6 mm Hg (mean ± s.e. mean) to 88.4 ± 7.4 mm Hg at 2 h (P < 0.05 when compared to placebo) and to 96.8 ± 2.2 mm Hg at 4 h (P < 0.05); diastolic pressure was reduced from 76.4 ± 4.1 mm Hg to 57.2 ± 6.4 mm Hg at 2 h (P < 0.01) and to 64.4 ± 4.3 mm Hg at 4 h (P < 0.05). The reductions in arterial pressure were accompanied by an increase in heart rate from 94.0 ± 4.5 beats min^-1 to 102.0 ± 7.0 beats min^-1 at 2 h, and to 104.6 ± 8.1 beats min^-1 at 4 h (P < 0.05 when compared to placebo, but not when compared to the pre-treatment value). Similar changes were observed on day 4 after 50 mg indoramin, but the maximum reduction in arterial pressure was observed at 2 h on day 1, and 4 h on day 4.

7 Indoramin 100 mg reduced systolic arterial pressure in the standing position on day 1 from 114.0 ± 2.6 mm Hg to 99.2 ± 5.8 mm Hg at 2 h, and to 88.0 ± 5.9 mm Hg at 4 h (P < 0.01); diastolic pressure was reduced from 80.4 ± 3.4 mm Hg to 64.4 ± 3.2 mm Hg at 2 h (P < 0.05), and to 64.0 ± 4.5 mm Hg at 4 h (P < 0.05). The reduction in arterial pressure was accompanied by a small increase in heart rate from 102.2 ± 8.3 beats min^-1 to 107.2 ± 12.7 beats min^-1 at 2 h (P < 0.05 when compared to placebo, but not when compared to the pre-treatment value); no change in heart rate was observed at 4 h. The changes in arterial pressure and heart rate observed on day 4 after 100 mg indoramin were less than those observed on day 1, but these differences were not significant.

8 Indoramin reduces arterial pressure in normal man, but it is not possible to describe a dose-response relationship for the reduction. The reduction is accompanied by only a small increase in heart rate, possibly due to a direct bradycardic action of indoramin on the heart.

Cardiovascular effects of intravenous indoramin hydrochloride in man

Haemodynamic effects of intravenous indoramin (5-20 mg) were measured in ten healthy volunteers. Slight falls in arterial and central venous blood pressures were noted but no significant changes in heart rate, right atrial pressure, cardiac output or derived values occurred, except for a fall in peripheral vascular resistance in three cases. An increase in skin blood flow to the feet was observed. An attempt was made to determine the mechanisms of these responses and it was concluded that the drug was an alpha adrenoceptor blocking agent which appeared to act preferentially on those receptors controlling blood flow to the skin of extremities.

On the mechanisms of hypotensive action of indoramin

Effect of indoramin in small doses on the central vasomotor loci has been studied in chloralose anesthetized cats by localizing it to the central sites. An intracerebroventricular dose of 100 micrograms or intra-vertebral arterial injection of 50 micrograms significantly inhibited the excitability of hypothalamic and medullary vasomotor loci and produced hypotension. Similarly, topical application of indoramin (0.5%) to the floor of the IV ventricle inhibited the medullary and the hypothalamic vasomotor responses but a similar application to the ventral surface of the medulla had no effect. An intrathecal dose of 100 micrograms did not inhibit the spinal compression vasmotor response. Administration of higher amounts led to inhibition of the adrenaline pressor response also, indicating a peripheral leak of the drug. Indoramin has a definite inhibitory effect on the medullary vasomotor loci which contributes to the hypotension produced by this drug.

Pharmacokinetics of indoramin in man

1 The fate of oral and intravenous indoramin has been studied after single doses in man using the 14C labelled drug. Plasma concentrations of indoramin have been determined during chronic oral antihypertensive therapy employing a stable isotope dilution assay. 2 Following singleoral dosing the drug is well absorbed and extensively metabolised. Faecal excretion in 72 h accounts for 46% of the administered radioactivity of which approximately 4% is associated with indoramin. Less than 2% of the radioactivity in urine is accountable as the concentration of total metabolites. Peak plasma levels both of drug and metabolites occur 1-2 h after dosing, the maximal lowering of blood pressure occurring at this time. 3 The clearance of indoramin, determined after intravenous administration is of the same order as liver blood flow. In the isolated perfused rat liver, the extraction ratio is 0.98.

Indoramin in the treatment of hypertension: a placebo controlled trial

The effect of the alpha-blocker indoramin was studied in a 4-week double-blind comparative trial with placebo in 39 patients with mild to moderate essential hypertension. Dosage of indoramin was individually adjusted and ranged from 125 mg to 200 mg daily. Indoramin produced a significantly greater reduction in diastolic blood pressure than placebo, and 9 (56%) out of 16 patients attained diastolic pressures of 90 mmHg or less. Heart rate, haematology and blood biochemistry were unaffected by treatment with indoramin, and there were no E.C.G. changes. Nine out of 19 patients on indoramin complained of side-effects. These were generally not troublesome, although 3 patients withdrew because of severe tiredness or weight gain.