Plasma timolol levels and systolic time intervals

Topical Application of 0.5% Timolol Maleate Hydrogel for the Treatment of Superficial Infantile Hemangioma

The therapeutic options for infantile hemangiomas (IHs) have been greatly altered since the introduction of oral propranolol for successful treatments of IHs. Recently, there is an increase in the application of topical timolol maleate for treating superficial IHs. In the present study, we developed a new formulation of timolol maleate 0.5% hydrogel and treated 321 patients with superficial IHs to evaluate its efficacy and safety in the treatment of superficial IHs. This new timolol hydrogel was applied three times daily with a mean duration of 7.1 months. Response to treatment was assessed according to cosmetic improvement by using visual analog scale (VAS). The average VAS improvement after treatment was 76.4, with 126 patients (39.3%) achieving excellent responses, 159 patients (49.5%) achieving good responses, 33 patients (10.3%) achieving fair responses, and three patients (0.9%) achieving poor responses. Age at treatment initiation (P = 0.0349) and lesion thickness (P = 0.0147) were significantly associated with therapeutic efficacy. No severe side effects were observed in all patients. In conclusion, this new topical timolol maleate 0.5% hydrogel appears to be a proper candidate for treating superficial IHs, and our study provides supportive evidence and experience of topical timolol maleate in treating superficial IHs.

Topical Timolol Maleate Treatment of Infantile Hemangiomas

BACKGROUND

There has been a dramatic increase in the off-label use of ophthalmic timolol maleate, a β-blocker used for infantile hemangioma (IH) treatment as a topical counterpart to oral propranolol. Its safety and efficacy in a pediatric population with IH have not been evaluated in a large cohort. Our goal was to retrospectively assess timolol's effectiveness, discern characteristics associated with response, and document reported adverse events.

METHODS

A multicenter retrospective cohort study of 731 patients treated with topical timolol was completed at 9 centers. Inclusion required an IH suitable for timolol in the treating physician's judgment and access to clinical details including photographs. Logistic regression analysis and descriptive statistics were performed. Primary outcome measures were efficacy assessed by using visual analog scales for color and for size, extent, and volume from review of digital photographs taken as standard of care.

RESULTS

Most IHs were localized (80.1%) and superficial (55.3%). Risk of disfigurement was the most common indication for therapy (74.3%). Duration of therapy (P < .0001), initial thinness (P = .008), and subtype (P = .031) were significant predictors of response. Best response occurred in superficial IHs <1 mm thick. Fifty-three (7.3%) required subsequent therapy with systemic β-blocker. Adverse events were mild, occurring in 25 (3.4%) patients. No cardiovascular side effects were documented.

CONCLUSIONS

Timolol seems to be a well-tolerated, safe treatment option with moderate to good effectiveness, demonstrating best response in thin, superficial IHs regardless of pretreatment size. Timolol can be recommended as an alternative to systemic β-blockers and watchful waiting for many patients.

Topical Timolol for Infantile Hemangiomas: Evidence for Efficacy and Degree of Systemic Absorption

BACKGROUND

Topical use of timolol for infantile hemangiomas has recently emerged with promising results. It is unknown whether topical β-blockers act locally or if their effect is partly due to systemic absorption. This study investigates whether topically applied timolol is absorbed and reports on the efficacy of this treatment.

METHODS

We treated 40 infants with small proliferating hemangiomas with topical timolol gel 0.5% twice daily and assessed urinary excretion and serum levels in a proportion of patients. Clinical response was evaluated on a visual analog scale of standardized photographs after 1, 2, 3, and 5 months.

RESULTS

Forty infants with a median age of 18 weeks (range 2-35 wks) were included; 23 (58%) had superficial and 17 (42%) mixed-type hemangiomas. The median size was 3 cm(2) (range 0.1-15 cm(2) ) and nine hemangiomas were ulcerated. The hemangiomas improved significantly during treatment, with a median increase in visual analog scale of 7 points after 5 months (p < 0.001). Urinalysis for timolol was performed in 24 patients and was positive in 20 patients (83%). In three infants, serum levels of timolol were also measured and were all positive (median 0.16 ng/mL [range 0.1-0.18 ng/mL]). No significant side effects were recorded.

CONCLUSION

Topical therapy with timolol is effective for infantile hemangiomas, but systemic absorption occurs. Serum levels in our patients were low, suggesting that using timolol for small hemangiomas is safe, but caution is advised when treating ulcerated or large hemangiomas, very young infants, or concomitantly using systemic propranolol.

Outpatient use of oral propranolol and topical timolol for infantile hemangiomas: survey results and comparison with propranolol consensus statement guidelines

Oral and topical β-blockers are used to treat infantile hemangiomas (IHs). Although a recent consensus report provided guidelines for the treatment of IH with propranolol, there are no standard guidelines for the use of topical timolol. The objectives of this study were to determine the current use of oral propranolol and topical timolol by pediatric dermatologists in an outpatient setting and to compare current propranolol use with published propranolol consensus guidelines. An electronic survey was sent to pediatric dermatologists in May and June 2013. One hundred forty-nine pediatric dermatologists responded to the survey, a 79% response rate. Of the respondents, 96% prescribed oral propranolol, but 75% did not follow consensus guidelines exactly; recommended history, physical examination, initial dose, and frequency varied. The dose of propranolol was usually titrated up to goal dose as recommended (89%). Fifty-six percent monitored vital signs in patients after the initial dose and 49% continued to monitor vital signs in their clinic after each dose escalation, which did not meet consensus guideline recommendations. Ninety-one percent reported using topical timolol for the treatment of IH and 66% responded they had used topical timolol in conjunction with oral propranolol to treat IH. The most common indication was superficial hemangiomas (97%). Most practitioners (74%) did not routinely monitor heart rate or blood pressure in infants treated with topical timolol. This study highlights the variability in prescribing and monitoring practices of physicians using propranolol for the treatment of IHs and demonstrates that topical timolol is commonly used alone and in conjunction with oral propranolol to treat IHs.

Topical timolol for small hemangiomas of infancy

Propranolol has become the treatment of choice of large and complicated infantile hemangiomas. There is a controversy concerning the safety of systemic propranolol. Here we show that topical use of the beta-blocker timolol can also inhibit the growth and promote regression of infantile hemangiomas. In this case series we treated 11 infantile hemangiomas in nine children including six preterm babies with the nonselective betablocker timolol. A timolol containing gel was manufactured from an ophthalmic formulation of timolol 0.5% eyedrops. This gel was applied using a standardized occlusive dressing (Finn-Chambers) containing approximately 0.25 mg of timolol. In all infants topical timolol was associated with growth arrest, a reduction in redness and thickness within the first 2 weeks. Seven hemangiomas showed almost complete resolution, and four became much paler and thinner. No data are available on the transdermal absorption of timolol. Even supposing complete absorption of timolol from the occlusive dressing, a maximum dose of 0.25 mg of timolol would result per day and hemangioma. Regression of infantile hemangiomas treated using 0.5% timolol gel in this case series occurred earlier than spontaneous regression which is generally not observed before the age of 9-12 months. The promising results need to be verified in prospective randomized trials on topical beta blocker administration for infantile hemangiomas which should address dose, duration, and mode of application.

Timolol maleate 0.5% or 0.1% gel-forming solution for infantile hemangiomas: a retrospective, multicenter, cohort study

Therapeutic options for superficial infantile hemangiomas (IH) are limited. Recently, timolol maleate gel, a topical nonselective beta-blocker, has been reported as a potentially effective treatment for superficial IH. This study is an extension of a previously published pilot study designed to further investigate the efficacy and safety and to identify predictors of good response of topical 0.5% or 0.1% timolol maleate gel-forming solution. This was a retrospective cohort study including patients enrolled from five centers. Patients were included if they were treated with timolol maleate 0.1% or 0.5% gel-forming solution and had photographic documentation of the IH and at least one follow-up visit. Patients with concomitant active treatment using other IH treatments were excluded. The primary endpoint was change in the appearance of IH as evaluated using a visual analog scale (VAS). Data from 73 subjects were available for final analysis. Timolol maleate gel-forming solution 0.5% was used in 85% (62/73) of patients, the remainder being treated with 0.1%. The median age at treatment initiation was 4.27 months (interquartile range [IQR] 2.63-7.21 mos), and patients were treated for a mean of 3.4 ± 2.7 months. All patients except one improved, with a mean improvement of 45 ± 29.5%. Predictors of better response were superficial type of hemangioma (p = 0.01), 0.5% timolol concentration (p = 0.01), and duration of use longer than 3 months (p = 0.04). Sleeping disturbance was noted in one patient. This study further demonstrates the efficacy and tolerability of topical timolol maleate and gradual improvement with longer treatment in patients with superficial IH.

Pharmacodynamic modeling of digoxin-induced bradycardia

Digoxin-induced bradycardia in dogs was used to evaluate several pharmacodynamic models. Digoxin plasma concentrations and response were monitored in beagle dogs administered either 0.05 or 0.025 mg/kg of digoxin iv as an infusion over 5 min. The models investigated were the linking model, the linear model, the effect compartment model, and the inhibitory model. Regression procedures for investigating the effect compartment model were conducted with Emax (the maximal response, where response was the percentage decrease in heart rate) as a variable with an upper bound of 100%, with a constant value of 100%, or alternately with a constant value equal to the maximal observed response. Based on statistical criteria the effect model using Emax as a variable was found to be the best model for describing digoxin-induced bradycardia. For the effect compartment model, CPss(50) (concentration at steady state that will produce 50% of the maximal response) ranged from 3.8-9.8 ng/ml; delta (exponent describing the steepness of the concentration-response relationship) ranged from 0.6-7.1. The implication of these models in understanding concentration-effect relationships are discussed.

Influence of beta blockade and intrinsic sympathomimetic activity on hemodynamics, inotropy and respiration at rest and during exercise

The degree of intrinsic sympathomimetic activity (ISA) is reported to influence the effects of beta blockade at rest, but the effects during exercise are not well documented. Heart rate, blood pressure and left ventricular (LV) function (as assessed by systolic time intervals) were measured at rest and during upright bicycle exercise as well as with flow-volume spirometry at rest in 13 healthy volunteers. The measurements were performed before and 4 and 24 hours after a single oral dose of pindolol (10 mg), nadolol (80 mg) and acebutolol (400 mg) in a double-blind, randomized, crossover manner. All drugs reduced heart rate, but nadolol had the most pronounced and longest bradycardic effect at rest. Diastolic blood pressure was only slightly influenced by the drugs, whereas systolic pressure was significantly lower compared with control values, especially during exercise (p less than 0.001). Neither preejection period (PEP) nor LV ejection time (LVETc) was changed at rest after pindolol, but PEP increased and LVETc decreased significantly after nadolol (p less than 0.05 for PEP and p less than 0.01 for LVETc) and acebutolol (p less than 0.05 for both). During exercise, PEP and LVET were significantly longer after all 3 drugs compared with control values. Only nadolol, which lacks ISA, significantly decreased expiratory flow values (p less than 0.05). Thus, unlike the other beta blockers, pindolol (with strong ISA) did not depress LV function at rest, while during exercise all 3 beta blockers had equal adverse effects. The degree of ISA appears to be important in determining the hemodynamic effects of beta-blocking drugs.

Beta-blocking potency and electrophysiologic effects of acebutolol

The beta-blocking potency of three doses of acebutolol (100, 200, and 600 mg three times a day) has been compared to that of propranolol (30, 60, and 180 mg three times a day) in a double-blind crossover study in 10 healthy volunteers (seven men, three women). On the basis of reduction in resting and exercise heart rates, propranolol was three to four times more potent than acebutolol on a milligram-for-milligram basis. Plasma levels showed large interindividual variation for both agents. Plasma levels were weakly correlated with the degree of beta blockade for both acebutolol (r = 0.333, p less than 0.001) and propranolol (r = 0.381, p less than 0.01). Dose and percent beta blockade were more strongly correlated (propranolol, r = 0.503, p less than 0.001; acebutolol, r = 0.574, p less than 0.001). In 11 patients (10 men, one woman) with coronary artery disease, acebutolol at 1 mg/kg infused over 15 minutes decreased heart rate and slowed conduction, increased the refractoriness of the atrioventricular node without a significant change in the atrial refractoriness, and at plasma levels greater than or equal to 1000 ng/ml slowed His-Purkinje conduction. The comparative potency data suggest that the magnitude of the decrease in the resting and exercise-induced changes in heart rate and double product, in relation to dose of acebutolol, provides quantitative indices for judging adequacy by beta blockade in clinical therapeutics. The use of plasma drug levels, however, does not appear to be helpful in judging the adequacy of beta blockade.(ABSTRACT TRUNCATED AT 250 WORDS)