The medication most commonly associated with the development of oral candidiasis is inhaled corticosteroids.

- Oral candidiasis, also known as oral thrush, is a fungal infection caused by the overgrowth of Candida species, particularly Candida albicans, in the oral mucosa.
- The use of certain medications can predispose to this condition by disrupting the normal flora or local immunity.

- Inhaled corticosteroids are widely used in the management of asthma and chronic obstructive pulmonary disease (COPD). These drugs deposit corticosteroid particles in the oropharynx, leading to localized immunosuppression. This local suppression of immune defenses enables Candida to proliferate, resulting in oral candidiasis. The risk is increased if patients do not rinse their mouth after inhaler use.

- Systemic antibiotics can also predispose to candidiasis by disrupting normal bacterial flora, but they are more commonly associated with candidiasis in other sites such as the gastrointestinal tract or vaginal mucosa rather than primarily in the oral cavity.

- Oral beta-blockers and topical nonsteroidal anti-inflammatory drugs (NSAIDs) do not have a well-established association with the development of oral candidiasis.

In summary, inhaled corticosteroids are the most common medication class linked to the development of oral candidiasis due to localized immunosuppression in the oral mucosa.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Volume 2, Chapter 330: Fungal infections