Dequalinium is a quaternary ammonium compound developed in the mid-20th century, primarily for its antiseptic and antimicrobial properties. It has been used in topical and local applications, including oral rinses, vaginal tablets, and wound care, due to its broad-spectrum activity against Gram-positive and Gram-negative bacteria, fungi, and some viruses. Dequalinium works by disrupting microbial cell membranes, leading to cell death. Its development focused on providing a safe, locally acting antimicrobial with minimal systemic absorption, making it suitable for treating oral infections, bacterial vaginosis, and surface wounds. The drug is valued for its low systemic toxicity and effectiveness in environments where conventional systemic antibiotics may not be necessary or desirable.
BRAND NAMES
Fluomizin – commonly used as vaginal tablets for bacterial vaginosis
Dequadin – used as an oral antiseptic lozenge or solution in some regions.
MECHANISM OF ACTION
Dequalinium is a quaternary ammonium compound that exerts its antimicrobial effect by disrupting microbial cell membranes. Its positively charged structure interacts with the negatively charged components of bacterial, fungal, or viral cell membranes, causing increased membrane permeability, leakage of cellular contents, and ultimately cell death.
PHARMACOKINETICS
Absorption
Dequalinium is poorly absorbed systemically when administered via topical or mucosal routes, such as vaginal tablets, oral rinses, or surface applications. Its local effect is the primary therapeutic mechanism, targeting microbial populations directly at the site of application.
Distribution
Because dequalinium is poorly absorbed systemically, its volume of distribution isvery low. The drug primarily remains at the site of application (oral cavity, vaginal mucosa, or skin), where it exerts its antimicrobial effects.
Metabolism
Dequalinium undergoes minimal to negligible systemic metabolism due to its poor absorption from topical or mucosal applications. The majority of the drug remains at the site of application, exerting its antimicrobial effects locally.
Elimination
Dequalinium is primarily eliminated locally at the site of application, with the majority of the drug remaining bound to mucosal tissues or secretions. Minimal systemic absorption means that very little enters the bloodstream; any absorbed fraction is excreted largely unchanged via the urine and feces.
PHARMACODYNAMICS
Dequalinium exerts its pharmacological effect primarily through local antimicrobial activity. As a quaternary ammonium compound, it interacts with the negatively charged components of microbial cell membranes, disrupting membrane integrity and causing leakage of cellular contents, which leads to microbial death.
ADMINISTRATION
Dequalinium is administered topically or locally, depending on the formulation and intended use. For vaginal infections such as bacterial vaginosis, it is usually given as vaginal tablets, inserted once daily, typically at bedtime, for a prescribed duration (commonly 6–12 days). For oral infections, it may be used as a lozenge or mouth rinse, allowing prolonged contact with the oral mucosa.
DOSAGE AND STRENGTH
Dequalinium is commonly available in vaginal tablets of 10 mg and oral lozenges or rinses with comparable low-dose formulations. For the treatment of bacterial vaginosis, the usual adult dose is one 10 mg vaginal tablet once daily, typically administered at bedtime for 6 consecutive days.
DRUG INTERACTIONS
Dequalinium has minimal systemic absorption, so the risk of systemic drug interactions is very low. However, its local antimicrobial effectiveness can be affected by the concurrent use of other topical or mucosal products, such as antiseptics, surfactants, or medications that significantly alter local pH.
FOOD INTERACTIONS
Dequalinium is administered locally (vaginally, orally, or topically), and its therapeutic effect is not affected by food intake. Because it is poorly absorbed systemically, there are no significant interactions with meals or dietary components. Patients can take oral formulations or use vaginal tablets regardless of meals.
CONTRAINDICATIONS
Dequalinium is contraindicated in individuals with a known hypersensitivity to dequalinium or any component of its formulation. It should not be used in patients with severe mucosal irritation or open wounds at the site of application, as this may increase local irritation or discomfort.
SIDE EFFECTS
Local irritation or burning at the site of application
Itching or mild discomfort in the vaginal or oral mucosa
Dryness of the treated area
Temporary altered taste (for oral formulations)
Rare allergic reactions, including rash or swelling
Mild gastrointestinal upset if swallowed accidentally
Rare hypersensitivity reactions.
OVER DOSAGE
Overdose of dequalinium is rare due to its minimal systemic absorption, but excessive ingestion or prolonged inappropriate use can lead to local irritation, burning, or discomfort in the mouth, throat, or vaginal mucosa. In cases of accidental oral ingestion of large amounts, mild gastrointestinal symptoms such as nausea, vomiting, or diarrhea may occur. Management of overdosage is primarily supportive, including discontinuation of the drug, symptomatic treatment of irritation, and hydration if gastrointestinal upset occurs. Serious systemic toxicity is extremely uncommon.
TOXICITY
Dequalinium exhibits low systemic toxicity due to its minimal absorption from topical or mucosal sites. Toxic effects are primarily local, such as irritation, burning, or itching at the site of application. Severe systemic toxicity is rare, but accidental ingestion of large amounts may cause mild gastrointestinal upset or, in very high doses, more pronounced symptoms such as nausea or vomiting.
