PHN is an acronym used for postherpetic neuralgia, a neuropathic pain.
PHN may also refer to: North Philadelphia station (Amtrak station code) Philippine highway network Phoenician language (ISO 639-2 and ISO 639-3 codes) Spanish National Water Plan (Plan Hidrológico Nacional); see Water supply and sanitation in Spain Public Health Nurse St. Clair County International Airport (IATA and FAA LID codes) p-Hydroxynorephedrine, an analog of norephedrine