Miconazole

Miconazole

Drug Nomenclature

Pharmacopoeias in Europe, Japan, and US

European Pharmacopoeia, 6th ed. (Miconazole)

A white or almost white powder. It exhibits polymorphism. M.p. 83° to 87°. Very slightly soluble in water soluble in alcohol freely soluble in methyl alcohol. Protect from light.

The United States Pharmacopeia 31, 2008 (Miconazole)

A white to pale cream powder. It may exhibit polymorphism. M.p. 78° to 88°. Insoluble in water soluble 1 in9.5 of alcohol, 1 in 2 of chloroform, 1 in 15 of ether, 1 in4 of isopropyl alcohol, 1 in 5.3 of methyl alcohol, and 1 in 9 of pro-pylene glycol freely soluble in acetone and in dimethylforma-mide. Store at a temperature of 25°, excursions permitted between 15° and 30°. Protect from light.

Miconazole Nitrate

Drug Approvals

Pharmacopoeias in China, Europe, International, Japan, and US

European Pharmacopoeia, 6th ed. (Miconazole Nitrate)

A white or almost white powder. Very slightly soluble in water slightly soluble in alcohol sparingly soluble in methyl alcohol. Protect from light.

The United States Pharmacopeia 31, 2008 (Miconazole Nitrate).

A white or practically white, crystalline powder, with not more than a slight odour. Soluble 1 in 6250 of water, 1 in 312 of alcohol, 1 in 75 of methyl alcohol, 1 in 525 of chloroform, 1 in 1408 of isopropyl alcohol, 1 in 119 of propylene glycol freely soluble in dimethyl sulfoxide soluble in dimethylformamide insoluble in ether. Protect from light.

Adverse Effects

After oral use of miconazole, nausea and vomiting have been reported, and also diarrhoea (usually on long-term treatment). There have been allergic reactions, rarely, and isolated reports of hepatitis. Local irritation and sensitivity reactions may occur when miconazole nitrate is used topically contact dermatitis has been reported. After the intravenous infusion of miconazole, phlebitis, nausea, vomiting, diarrhoea, anorexia, pruritus, rash, febrile reactions, flushes, drowsiness, and hyponatraemia have been reported. Other effects include hyperlipidaemia, aggregation of erythrocytes, anaemia, and thrombocytosis. Transient tachycardia and other cardiac arrhythmias have followed the rapid intravenous injection of miconazole (but see also Effects on the Heart, below). Rare adverse effects include acute psychosis, arthralgia, and anaphylaxis. Many of these adverse effects have been associated with the injection vehicle, which contains polyoxyl castor oil.

Effects on the heart

Bradycardia, progressing to fatal ventricular fibrillation and cardiac arrest, occurred in a heart transplant patient during intravenous infusion of miconazole for an invasive fungal infection

Overdosage

A report of a generalised tonic-clonic convulsion that occurred in an infant 10 to 15 minutes after the inadvertent infusion of miconazole 500 mg instead of 50 mg.

Precautions

Miconazole oral gel should be avoided in patients with hepatic impairment. Intravaginal preparations of miconazole may damage latex contraceptives and additional contraceptive measures are therefore necessary during local application. Miconazole has been fetotoxic at high doses in animals and its use is generally not recommended during pregnancy. For a discussion of the caution needed when using azole antifungals during pregnancy, see under Pregnancy in Precautions of Fluconazole. Porphyria. Miconazole is considered to be unsafe in patients with porphyria because it has been shown to be porphyrinogenic in in-vitro systems.

Interactions

Miconazole can inhibit the metabolism of drugs metabolised by the cytochrome P450 isoenzymes CYP3 A4 and CYP2C9, and may thus have effects similar to those of fluconazole. Miconazole may enhance the activity of oral anticoagulants, sulfonylurea hypoglycaemics, or phenytoin. Adverse effects have been reported when miconazole was given with carbamazepine. There is a risk of cardiac arrhythmias if miconazole is used with astemizole, cisapride, or terfenadine and such combinations should be avoided.

Anticoagulants

The anticoagulant activity of coumarin anticoagulants can be potentiated by miconazole given orally, intra-vaginally, or topically. As of December 2002 the Australian Adverse Drug Reactions Advisory Committee had received 18 reports of significant increases in the INR of patients previously stabilised on warfarin within 1 to 2 weeks of starting treatment with miconazole oral gel.

Antimicrobial Action

Miconazole is an imidazole antifungal with similar antimicrobial activity to that of ketoconazole. It also has some activity against Aspergillus spp., Cryptococcus neoformans, Pseudallescheria boydii, and some Gram-positive bacteria including staphylococci and streptococci.

Microbiological interactions

A study in vitro indicating antimicrobial synergism of miconazole and benzoyl peroxide against Staphylococcus spp. and Propionibacterium acnes For the effect on antifungal activity of giving azoles and amphotericin B together.

Pharmacokinetics

Miconazole is incompletely absorbed from the gastrointestinal tract. Peak plasma concentrations of 1 microgram/mL are achieved about 4 hours after a dose of 1 g daily. Over 90% is reported to be bound to plasma proteins. Miconazole is metabolised in the liver to inactive metabolites. From 10 to 20% of an oral dose is excreted in the urine, mainly as metabolites, within 6 days. About 50% of an oral dose maybe excreted unchanged in the faeces. The elimination pharmacokinetics of miconazole have been described as triphasic, with a biological half-life of about 24 hours. Very little miconazole is removed by haemodialysis. There is little absorption through skin or mucous membranes when miconazole nitrate is applied topically.

Uses and Administration

Miconazole is an imidazole antifungal used as miconazole base or nitrate in the treatment of superficial candidiasis, and of the skin infections dermatophytosis and pityriasis versicolor. It has also been given intravenously by infusion in the treatment of disseminated fungal infections, but other azoles are now more commonly used. Miconazole may be given orally as a gel containing 20 mg/g (24 mg/mL) for the treatment of oropharyngeal and intestinal candidiasis. The usual adult dose is 5 to 10 mL four times daily (equivalent to a total of about 15 mg/kg daily). Children under the age of 2 years may be given the oral gel in a dose of 2.5 mL twice daily those aged between 2 and 6 years, 5 mL twice daily and those aged over 6 years, 5 mL four times daily. For the treatment of oral lesions the oral gel is applied directly.

Miconazole nitrate is usually applied twice daily as a 2% cream, lotion, or powder in the treatment of fungal infections of the skin including candidiasis, dermato-phytosis, and pityriasis versicolor. In the treatment of vaginal candidiasis, 5 g of a 2% intravaginal cream is inserted into the vagina once daily for 10 to 14 days or twice daily for 7 days. Miconazole nitrate pessaries may be inserted in dosage regimens of 100 mg once daily for 7 or 14 days, 100 mg twice daily for 7 days, 200 or 400 mg daily for 3 days, or in a single dose of 1200 mg.

Acanthamoeba keratitis

Miconazole has been applied topically in A canthamoeb a keratitis in combination with systemic treatment with either ketoconazole or itraconazole.

Skin disorders

Topical preparations containing an imidazole such as ketoconazole or miconazole, usually with hydrocortisone, are used in the management of seborrhoeic dermatitis. A cream containing miconazole nitrate 2% and benzoyl peroxide 5% has been used topically in the treatment of acne.

Preparations

British Pharmacopoeia 2008:

Miconazole and Hydrocortisone Acetate Cream Miconazole and Hydrocortisone Cream Miconazole and Hydrocortisone Ointment Miconazole Cream Miconazole Oromucosal Gel

The United States Pharmacopeia 31, 2008:

Miconazole Injection Miconazole Nitrate Cream Miconazole Nitrate Topical Powder Miconazole Nitrate Vaginal Suppositories.

Proprietary Preparations

Multi-ingredient

The symbol denotes a preparation no longer actively marketed