Antifungal Medications
In dentistry and oral care medicine, antifungal medications are prescribed less compared to conventional analgesic or antibiotics. However, it is mandatory that a clinician or dentist is familiar with common antifungal indications and medications available in the market. Antifungals are used to treat oral candidiasis. Oral candidiasis is known to cause complex oral health problems. Oral and pharyngeal candidiasis is caused by the primary fungal organism Candida albicans. Oral candidiasis is listed as an acquired immunodeficiency syndrome by the Centers for Disease Control and Prevention. Due to imbalances in the oral flora, patients using oral antibiotics could develop case of oral candidiasis. Patients belonging to the immunosuppressive category, cancer patients and diabetics have high chances of acquiring oral candidiasis. This paper would discuss about the common antifungal medications used as oral medication and in the dentistry field. Some antifungal medications (conventional) are effective in cases of immunosuppressive patients. Special care and treatment should be given to such patients. The paper would discuss on 3 popular antifungal medications used worldwide.
NYSTATIN: The mechanism of polyene antifungal medications have been widely studied. Nystatin is widely used antifungal medicine and combines with ergosterol (constituent of fungal cell membrane). This causes porosities in the membrane that ultimately causes death of the fungal organism. Nystanin is prescribed as dissolvable torches, topical ointment or oral suspension. The adult dose of nystanin (oral suspension) is around 400,000- 600,000 units for four times a day. Cheilitis (an infection at the corners of the mouth) can be treated by the topical ointment formulation of nystanin.
Azole antifungal agents: Systemic fungal infections can be treated using Azole antifungal agents. The conversion of lanosterol to ergosterol is possible through the interaction of azole antifungal agents with specific enzymes. Lack of ergisterol in the fungal cell membrane causes death of the organism. Common example of antifungal drugs used in dentistry are ketoconazole, clotrimazole and fluconazole.
Fluconazole: Oropharyngeal candidiasis can be treated by oral formulations of fluconazole. Oral tablets and IV formulations of fluconazole are also available. Fluconazole is used to treat patients who have not responded to nystanin. However, fluconazole can exacerbate existing hepatic or renal problems. Nausea, vomiting, diarrhea, dizziness and headache are common side-effects of fluconazole treatment. An adult dose of fluconazole for oropharyngeal is around 100-200 mg daily for a period of 7 to 14 days. Fluconazole is known for adverse drug interactions and precaution should be taken while administering fluconazole. Some medications cause hypertension when interacted with fluconazole. Hence, it is imperative that a dentist or clinical be aware of the potential interaction to therapeutic drugs a patient is already taking.
Ketoconazole: The mechanism of ketoconazole is similar to fluconazole. The recommended dose of ketoconazole is 200-800 mg (SINGLE DOSE ONLY) and it depends on the virulence of the fungal infection. Antacids used by people may have effect on the bioavailability of ketoconazole. Toxicity studies of ketoconazole showed accumulation of the drug in the adipose tissue. The use of ketoconazole is not recommended for patients with hepatic impairment. Ketoconazole can be used for oro-facial infections. The use of ketoconazole was given limited approval by the FDA in 2013. It could be used only if alternative drugs were not available.
Clotrimazole: Clotrimazole is available in torches or cream. It is used in the treatment of oropharyngeal candidiasis and is manufactured as 10-gm dose. The normal dose for an adult would be around 4 to 5 torches per day for a term of 14 days. Good oral hygiene should be maintained since clotrimazole has a high sugar content. After dissolution, clotrimazole is present for several hours in the saliva. Oral suspension of clotrimazole is available for patients with medications that cause reduced salivary flow. Oral mucosal irritation is a common side-effect of clotimaole. No adverse drug interactions of clotrimazole have been reported till date.
ANTIVIRAL MEDICATIONS: Viral diseases have a broad range of virulence and also have high degree of morbidity. Vural organisms infect all organ systems and tissues of the human body. Many viral diseases are incurable with a few in exception. Antiviral medications help in managing the virulence of the viral outbreaks. Nowadays, viral medications have been employed to treat maxillofacial and oral infections. Viral pathologies of maxillofacial and oral complex can be treated by common antiviral medications like valacyclovir and acyclovir. In some cases, famciclovir, penciclovir and gancicclovir have been used for the treatment of oral (viral) infections. Each drug is known for its own side-effects, drug interactions and spectrum of activity. In dentistry, antiviral medications are rarely used. However, it is advised that clinicians have thorough knowledge of these medications and their possible side-effects.
ACYCLOVIR: The reactivation of the herpes simplex virus-1 (HSV-1) causes most common oral lesion. These lesions lie in the regional nerve ganglion and lie dormant for years. Reactivation of HSV-1 infection can be triggered by sunlight, illness and emotional stress. Small, fluid-filled vesicles around the mucocutaneous junction of the skin and lips are a classic representation of the herpes labialis. In healthy patients, the vesicles form large lesions that crust and ulcerate (heal) after 2 weeks. Malaise and discomfort are common problems experienced by patients with herpes. Recurrence and longer healing times of herpes is seen in patients with HIV/AIDS. The mechanism of acyclovir is different from antibiotic and antifungal medications. Viral replication is prevented in patients administered to acyclovir. This is possible because the drug incorporates into the viral DNA. The derivatives of acyclovir are highly selective for viral DNA only. This prevents collateral damage to the host mammalian cells. However, the bioavailability of oral acyclovir is low (15% to 30%). Immunocompromised patients can opt for intravenous formulations of acyclovir. However, there are topical and oral formulations available. A special applicator can be used to apply the topical form of acyclovir that would decrease viral shedding. Direct contact with the fingertips and the viral lesions should be avoided by the patients. Direct contact with the viral lesions could result in the recurrence of the viral infection. The infection could spread to the finger (herpetic whitlow). The adult dose for oral acyclovir is around 200-400 mg (3 to 5 times a day). The extent of viral involvement would determine the duration of the treatment. Cramping, vomiting, nausea and abdominal cramping are common side-effects of acyclovir.
VALACYCLOVIR: In the gastrointestinal tract and the liver, valacyclovir is converted to acyclovir. It is known fact that valacyclovir is an ester of acyclovir. Infections caused by the herpes simplex virus is treated using valacyclovir. However, valacyclovir is available in an oral formulation only. It has limited activity against the Epstein-Barr virus. Compared to acyclovir, valacyclovir has higher bioavailability. The gastrointestinal side-effects of acyclovir are similar to valacyclovir. Some studies aslo suggest that the drug interactions of both the drugs are similar. The use of valacyclovir is not recommended for immunocompromised patients. Thrombocytopenic purpura have been reported in immunocompromised patients administered to valacyclovir. An alternative antiviral medication should be used in case of immunocompromised patients and consultation of a clinician should be taken prior to treatment.
References
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Newman MG, van Winkelhoff AJ (eds). Antibiotic and Antimicrobial Use in Dental Practice. 2nd ed. Chicago, IL: Quintessence; 2001.
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American Dental Association. ADA Guide to Dental Therapeutics. 3rd ed. Chicago, IL: American Dental Association; 2003.
U.S. Food and Drug Administration. (2013). FDA Limits Usage of Nizoral (ketoconazole) Oral Tablets Due to Potentially Fatal Liver Injury and the Risk of Drug Interactions and Adrenal Gland Problems.
