Cost effectiveness of oral terbinafine (Lamisil) compared with oral fluconazole (Diflucan) in the treatment of patients with toenail onychomycosis

A Week of Oral Terbinafine Pulse Regimen Every Three Months to Treat all Dermatophyte Onychomycosis

Terbinafine has proved to treat numerous fungal infections, including onychomycosis, successfully. Due to its liver metabolization and dependency on the cytochrome P450 enzyme complex, undesirable drug interaction are highly probable. Additionally to drug interactions, the treatment is long, rising the chances of the appearance of side effects and abandonment. Pharmacokinetic data suggest that terbinafine maintains a fungicidal effect within the nail up to 30 weeks after its last administration, which has aroused the possibility of a pulse therapy to reduce the side effects while treating onychomycosis. This study's goal was to evaluate the effectiveness of three different oral terbinafine regimens in treating onychomycosis due to dermatophytes. Sixty-three patients with onychomycosis were sorted by convenience in three different groups. Patients from group 1 received the conventional terbinafine dose (250 mg per day for 3 months). Group 2 received a monthly week-long pulse-therapy dose (500 mg per day for 7 days a month, for 4 months) and group 3 received a 500 mg/day dose for 7 days every 3 months, totaling four treatments. There were no statistical differences regarding the effectiveness or side effects between the groups. Conclusion: A quarterly terbinafine pulse regimen can be a possible alternative for treating onychomycosis caused by dermatophytes.

Oral antifungal medication for toenail onychomycosis

BACKGROUND

Fungal infection of the toenails, also called onychomycosis, is a common problem that causes damage to the nail's structure and physical appearance. For those severely affected, it can interfere with normal daily activities. Treatment is taken orally or applied topically; however, traditionally topical treatments have low success rates due to the nail's physical properties. Oral treatments also appear to have shorter treatment times and better cure rates. Our review will assist those needing to make an evidence-based choice for treatment.

OBJECTIVES

To assess the effects of oral antifungal treatments for toenail onychomycosis.

SEARCH METHODS

We searched the following databases up to October 2016: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials (RCTs). We sought to identify unpublished and ongoing trials by correspondence with authors and by contacting relevant pharmaceutical companies.

SELECTION CRITERIA

RCTs comparing oral antifungal treatment to placebo or another oral antifungal treatment in participants with toenail onychomycosis, confirmed by one or more positive cultures, direct microscopy of fungal elements, or histological examination of the nail.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 48 studies involving 10,200 participants. Half the studies took place in more than one centre and were conducted in outpatient dermatology settings. The participants mainly had subungual fungal infection of the toenails. Study duration ranged from 4 months to 2 years.We assessed one study as being at low risk of bias in all domains and 18 studies as being at high risk of bias in at least one domain. The most common high-risk domain was 'blinding of personnel and participants'.We found high-quality evidence that terbinafine is more effective than placebo for achieving clinical cure (risk ratio (RR) 6.00, 95% confidence interval (CI) 3.96 to 9.08, 8 studies, 1006 participants) and mycological cure (RR 4.53, 95% CI 2.47 to 8.33, 8 studies, 1006 participants). Adverse events amongst terbinafine-treated participants included gastrointestinal symptoms, infections, and headache, but there was probably no significant difference in their risk between the groups (RR 1.13, 95% CI 0.87 to 1.47, 4 studies, 399 participants, moderate-quality evidence).There was high-quality evidence that azoles were more effective than placebo for achieving clinical cure (RR 22.18, 95% CI 12.63 to 38.95, 9 studies, 3440 participants) and mycological cure (RR 5.86, 95% CI 3.23 to 10.62, 9 studies, 3440 participants). There were slightly more adverse events in the azole group (the most common being headache, flu-like symptoms, and nausea), but the difference was probably not significant (RR 1.04, 95% CI 0.97 to 1.12; 9 studies, 3441 participants, moderate-quality evidence).Terbinafine and azoles may lower the recurrence rate when compared, individually, to placebo (RR 0.05, 95% CI 0.01 to 0.38, 1 study, 35 participants; RR 0.55, 95% CI 0.29 to 1.07, 1 study, 26 participants, respectively; both low-quality evidence).There is moderate-quality evidence that terbinafine was probably more effective than azoles for achieving clinical cure (RR 0.82, 95% CI 0.72 to 0.95, 15 studies, 2168 participants) and mycological cure (RR 0.77, 95% CI 0.68 to 0.88, 17 studies, 2544 participants). There was probably no difference in the risk of adverse events (RR 1.00, 95% CI 0.86 to 1.17; 9 studies, 1762 participants, moderate-quality evidence) between the two groups, and there may be no difference in recurrence rate (RR 1.11, 95% CI 0.68 to 1.79, 5 studies, 282 participants, low-quality evidence). Common adverse events in both groups included headache, viral infection, and nausea.Moderate-quality evidence shows that azoles and griseofulvin probably had similar efficacy for achieving clinical cure (RR 0.94, 95% CI 0.45 to 1.96, 5 studies, 222 participants) and mycological cure (RR 0.87, 95% CI 0.50 to 1.51, 5 studies, 222 participants). However, the risk of adverse events was probably higher in the griseofulvin group (RR 2.41, 95% CI 1.56 to 3.73, 2 studies, 143 participants, moderate-quality evidence), with the most common being gastrointestinal disturbance and allergic reaction (in griseofulvin-treated participants) along with nausea and vomiting (in azole-treated participants). Very low-quality evidence means we are uncertain about this comparison's impact on recurrence rate (RR 4.00, 0.26 to 61.76, 1 study, 7 participants).There is low-quality evidence that terbinafine may be more effective than griseofulvin in terms of clinical cure (RR 0.32, 95% CI 0.14 to 0.72, 4 studies, 270 participants) and mycological cure (RR 0.64, 95% CI 0.46 to 0.90, 5 studies, 465 participants), and griseofulvin was associated with a higher risk of adverse events, although this was based on low-quality evidence (RR 2.09, 95% CI 1.15 to 3.82, 2 studies, 100 participants). Common adverse events included headache and stomach problems (in griseofulvin-treated participants) as well as taste loss and nausea (in terbinafine-treated participants). No studies addressed recurrence rate for this comparison.No study addressed quality of life.

AUTHORS' CONCLUSIONS

We found high-quality evidence that compared to placebo, terbinafine and azoles are effective treatments for the mycological and clinical cure of onychomycosis, with moderate-quality evidence of excess harm. However, terbinafine probably leads to better cure rates than azoles with the same risk of adverse events (moderate-quality evidence).Azole and griseofulvin were shown to probably have a similar effect on cure, but more adverse events appeared to occur with the latter (moderate-quality evidence). Terbinafine may improve cure and be associated with fewer adverse effects when compared to griseofulvin (low-quality evidence).Only four comparisons assessed recurrence rate: low-quality evidence found that terbinafine or azoles may lower the recurrence rate when compared to placebo, but there may be no difference between them.Only a limited number of studies reported adverse events, and the severity of the events was not taken into account.Overall, the quality of the evidence varied widely from high to very low depending on the outcome and comparison. The main reasons to downgrade evidence were limitations in study design, such as unclear allocation concealment and randomisation as well as lack of blinding.

Patient considerations in the management of toe onychomycosis - role of efinaconazole

Onychomycosis is a difficult diagnosis to manage and treatment is sometimes avoided, as this diagnosis is often wrongly perceived as a cosmetic problem. However, onychomycosis has a negative impact on patients' quality of life, affecting social interaction, psychological well-being, and physical activities. Onychomycosis is also a risk factor for patients with diabetes, with proven increased rates of cellulitis, gangrene, and foot ulcers. Treatments are only mild to moderately effective, and rates of relapse and reinfection are high. Oral treatments require laboratory monitoring due to risk of hepatotoxicity and may be contraindicated in some patients due to risk of drug-drug interactions. Topical treatments require prolonged application and are not very effective. Efinaconazole 10% solution is a new topical triazole treatment for mild to moderate distal subungual onychomycosis, with good efficacy and without the need for debridement of nails. In onychomycosis of the toenails, efinaconazole 10% solution is documented to have a statistically significant, positive impact on patient satisfaction and quality of life.

Pulse versus continuous terbinafine for onychomycosis: A randomized, double-blind, controlled trial

BACKGROUND

Effective treatments for onychomycosis are expensive. Previous studies suggest that less costly, pulsed doses of antifungal medications may be as effective as standard, continuous doses. Terbinafine is the current treatment of choice for toenail onychomycosis.

OBJECTIVE

Our purpose was to determine whether pulse-dose terbinafine is as effective as standard continuous-dose terbinafine for treatment of toenail onychomycosis.

METHODS

We conducted a double-blind, randomized, noninferiority, clinical intervention trial in the Minneapolis Veterans Affairs Medical Center. The main inclusion criteria for participants were a positive dermatophyte culture and at least 25% distal subungual clinical involvement. Six hundred eighteen volunteers were screened; 306 were randomized. Terbinafine, 250 mg daily for 3 months (continuous) or terbinafine, 500 mg daily for 1 week per month for 3 months (pulse) was administered. The primary outcome measure was mycological cure of the target toenail at 18 months. Secondary outcome measures included clinical cure and complete (clinical plus mycological) cure of the target toenail and complete cure of all 10 toenails.

RESULTS

Results of an intent-to-treat analysis did not meet the prespecified criterion for noninferiority but did demonstrate the superiority of continuous-dose terbinafine for: mycological cure of the target toenail (70.9% [105/148] vs 58.7% [84/143]; P =.03, relative risk [RR] of 1.21 [95% confidence interval (CI), 1.02-1.43]); clinical cure of the target toenail (44.6% [66/148] vs 29.3% [42/143]; P =.007, RR =1.52 [95% CI, 1.11-2.07); complete cure of the target toenail (40.5% [60/148] vs 28.0% [40/143]; P =.02, RR=1.45 [95% CI, 1.04-2.01); and complete cure of all 10 toenails (25.2% [36/143] vs 14.7% [21/143]; P =.03, RR =1.71 [95% CI, 1.05-2.79). Tolerability of the regimens did not differ significantly between the groups (chi2 =1.63; P =.65).

LIMITATIONS

The study population primarily consisted of older men with severe onychomycosis.

CONCLUSIONS

This study demonstrated the superiority of continuous- over pulse-dose terbinafine. We also found this expensive therapy to be much less effective than previously believed, particularly for achieving complete cure of all 10 toenails.

Terbinafine: a review of its use in onychomycosis in adults

Terbinafine, an orally and topically active antimycotic agent, inhibits the biosynthesis of the principal sterol in fungi, ergosterol, at the level of squalene epoxidase. Squalene epoxidase inhibition results in ergosterol-depleted fungal cell membranes (fungistatic effect) and the toxic accumulation of intracellular squalene (fungicidal effect). Terbinafine has demonstrated excellent fungicidal activity against the dermatophytes and variable activity against yeasts and non-dermatophyte molds in vitro. Following oral administration, terbinafine is rapidly absorbed and widely distributed to body tissues including the poorly perfused nail matrix. Nail terbinafine concentrations are detected within 1 week after starting therapy and persist for at least 30 weeks after the completion of treatment. Randomized, double-blind trials showed oral terbinafine 250 mg/day for 12 or 16 weeks was more efficacious than itraconazole, fluconazole and griseofulvin in dermatophyte onychomycosis of the toenails. In particular, at 72 weeks' follow-up, the multicenter, multinational, L.I.ON. (Lamisil vs Itraconazole in ONychomycosis) study found that mycologic cure rates (76 vs 38% of patients after 12 weeks' treatment; 81 vs 49% of recipients after 16 weeks' therapy) and complete cure rates were approximately twice as high after terbinafine treatment than after itraconazole (3 or 4 cycles of 400 mg/day for 1 week repeated every 4 weeks) in patients with toenail mycosis. Furthermore, the L.I.ON. Icelandic Extension study demonstrated that terbinafine was more clinically effective than intermittent itraconazole to a statistically significant extent at 5-year follow-up. Terbinafine produced a superior complete cure rate (35 vs 14%), mycologic cure rate (46 vs 13%) and clinical cure rate (42 vs 18%) to that of itraconazole. The mycologic and clinical relapse rates were 23% and 21% in the terbinafine group, respectively, compared with 53% and 48% in the itraconazole group. In comparative clinical trials, oral terbinafine had a better tolerability profile than griseofulvin and a comparable profile to that of itraconazole or fluconazole. Post marketing surveillance confirmed terbinafine's good tolerability profile. Adverse events were experienced by 10.5% of terbinafine recipients, with gastrointestinal complaints being the most common. Unlike the azoles, terbinafine has a low potential for drug-drug interactions. Most pharmacoeconomic evaluations have shown that the greater clinical effectiveness of oral terbinafine in dermatophyte onychomycosis translates into a cost-effectiveness ratio superior to that of itraconazole, fluconazole and griseofulvin.

CONCLUSION

Oral terbinafine has demonstrated greater effectiveness than itraconazole, fluconazole and griseofulvin in randomized trials involving patients with onychomycosis caused by dermatophytes. The drug is generally well tolerated and has a low potential for drug interactions. Therefore, terbinafine is the treatment of choice for dermatophyte onychomycosis.