The low systemic absorption of topical Terbisil renders overdosage extremely unlikely.
Symptoms
Accidental ingestion of one 30 g tube of Terbisil cream, which contains 300 mg Terbisil hydrochloride, is comparable to ingestion of one Terbisil 250 mg tablet (adult oral unit dose).
Should a larger amount of Terbisil cream be inadvertently ingested, adverse effects similar to those observed with an overdosage of Terbisil tablets are to be expected. These include headache, nausea, epigastric pain and dizziness.
Treatment
If accidentally ingested, the recommended treatment of overdosage consists of eliminating the active substance, primarily by the administration of activated charcoal, and giving symptomatic supportive therapy if needed.
Not applicable.
Local symptoms such as pruritus, skin exfoliation, application site pain, application site irritation, pigmentation disorder, skin burning sensation, erythema, scab, etc. may occur at the site of application.
These harmless symptoms must be distinguished from hypersensitivity reactions including rash, which are reported in sporadic cases and require discontinuation of therapy.
In case of accidental contact with the eyes Terbisil may be irritating to the eyes.
In rare cases the underlying fungal infection may be aggravated.
Adverse reactions are listed below by system organ class and the frequency. Frequencies are defined as: very common (>1/10), common (>1/100 to <1/10), uncommon (>1/1,000 to <1/100), rare (>1/10,000 to <1/1,000), very rare (<1/10,000), not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.
| Immune system disorders | |
| Not known: | Hypersensitivity* |
| Eye disorders | |
| Rare: | Eye irritation |
| Skin and subcutaneous tissue disorders | |
| Common: | Skin exfoliation, pruritus |
| Uncommon: | Skin lesion, scab, skin disorder, pigmentation disorder, erythema, skin burning sensation |
| Rare: | Dry skin, dermatitis contact, eczema |
| Not known: | Rash* |
| General disorders and administration site conditions | |
| Uncommon: | Pain, application site pain, application site irritation |
| Rare: | Condition aggravated |
* Based on post-marketing experience
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.
In long-term studies (up to 1 year) in rats and dogs no marked toxic effects were seen in either species up to oral doses of about 100 mg/kg a day. At high oral doses, the liver and possibly also the kidneys were identified as potential target organs.
In a two-year oral carcinogenicity study in mice, no neoplastic or other abnormal findings attributable to treatment were made up to doses of 130 (males) and 156 (females) mg/kg a day. In a two-year oral carcinogenicity study in rats at the highest dose level, 69 mg/kg a day, an increased incidence of liver tumours was observed in males. The changes, which may be associated with peroxisome proliferation, have been shown to be species-specific since they were not seen in the carcinogenicity study in mice or in other studies in mice, dogs or monkeys.
During the studies of high dose oral Terbisil in monkeys, refractile irregularities were observed in the retina at the higher doses (non-toxic effect level was 50 mg/kg). These irregularities were associated with the presence of a Terbisil metabolite in ocular tissue and disappeared after drug discontinuation. They were not associated with histological changes.
A standard battery of in vitro and in vivo genotoxicity tests revealed no evidence of a mutagenic or clastogenic potential for the drug.
No adverse effects on fertility or other reproduction parameters were observed in studies in rats or rabbits.
The treatment of tinea pedis (athlete's foot) and tinea cruris (dhobie itch/jock itch)
Fungal infections of the skin caused by dermatophytes such as species of Trichophyton (e.g. T. rubrum, T. mentagrophytes, T. verrucosum, T. violaceum), Microsporum canis and Epidermophyton floccosum.
Infections of the skin caused by Candida (e.g. Candida albicans).
Pityriasis (tinea) versicolor caused by Pityrosporum orbiculare (Malassezia furfur).
Pharmacotherapeutic group: Antifungal for topical use (ATC code D01A E15)
Terbisil is an allylamine that has a broad spectrum of antimycotic activity. It has an antimycotic effect on fungal infections of the skin caused by dermatophytes such as Trichophyton (e.g. T. rubrum, T. mentagrophytes, T. verrucosum, T. violaceum), Microsporum canis and Epdermophyton floccosum. At low concentrations Terbisil has a fungicidal effect against dermatophytes and moulds. Its activity against yeasts is fungicidal (e.g. Pityrosporum orbiculare or Malassezia furfur) or fungistatic, depending on the species.
Terbisil interferes specifically with fungal sterol biosynthesis at an early step. This leads to a deficiency in ergosterol and to an intracellular accumulation of squalene, resulting in fungal cell death. Terbisil acts by inhibition of squalene epoxidase in the fungal cell membrane.
The enzyme squalene epoxidase is not linked to the cytochrome P-450 system. Terbisil does not influence the metabolism of hormones or other drugs.
Less than 5% of the dose is absorbed after topical application to humans: systemic exposure is thus very low.
Terbisil 1 % Cream cream is for external use only.
Terbisil 1 % Cream cream may be irritating to the eyes. Contact with the eyes should be avoided. In case of accidental contact with the eyes, rinse eyes thoroughly with running water.
Terbisil cream should be kept out of the reach of children.
In the event of allergic reaction, the cream should be removed and the treatment interrupted.
Candidiasis: It is not recommended to use acid pH soap. (This provides favourable growth conditions for Candida spp.
Excipients
The cream contains cetyl alcohol and cetostearyl alcohol which may cause local skin reactions (e.g. contact dermatitis).
Terbisil 1 % Cream cream has no influence on the ability to drive and use machines.
Posology
Adults and adolescents (>12 years of age)
Duration and frequency of treatment:
Terbisil can be applied once or twice daily.
The likely duration of each treatment is as follows:
Tinea pedis: 1 week.
Tinea cruris and Tinea corporis: 1 to 2 weeks.
Cutaneous candida: 2 weeks.
Pityriasis versicolor: 2 weeks.
Relief of symptoms is usually obtained within a few days.
Irregular use or an inadequate treatment period increases the risk of the symptoms returning. If no improvement is obtained after 2 weeks, the diagnosis should be re-evaluated.
Elderly
There has been nothing to indicate that elderly patients require a different dosage or have a side effects profile different from younger patients.
Paediatric population
Terbisil 1 % Cream is not recommended for children below 12 years of age due to insufficient data on safety. The experience in children is limited.
Method of administration
For cutaneous use.
The skin should be clean and dry. The cream should be applied in a thin layer on and around the affected skin and rubbed in gently. In cases of reddened and weeping infection (under the breasts, between the fingers, buttocks or in the groin) the skin may be covered with a sterile compress after application of the cream, especially at night.
Not applicable
