Promethazine 25mg tablets are a prescription-only phenothiazine derivative medication that primarily functions as a sedating antihistamine. It is widely distributed under brand names like Phenergan. It works by blocking histamine receptors to halt allergic responses and altering certain chemicals in the brain to produce significant calming and anti-nausea effects.
Primary Medical Uses
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Allergy Relief: Alleviates seasonal or year-round allergies, hay fever, hives, rashes, and severe allergic reactions.
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Nausea and Vomiting: Prevents and manages severe nausea or vomiting triggered by illness, motion sickness, or following surgical anesthesia.
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Motion Sickness: Prevents space and travel sickness when taken in advance.
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Short-Term Insomnia & Sedation: Used short-term to treat severe sleeping difficulties in adults and to induce calm or light sleep before or after surgery.
Common Dosing Overview
“The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label.”
Typical guidelines include:
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Allergies: 25mg taken as a single dose at bedtime, or split into smaller 12.5mg doses before meals.
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Motion Sickness: 25mg taken 30 to 60 minutes before travel, repeated 8 to 12 hours later if required.
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Nausea / Vomiting: 25mg every 4 to 6 hours as needed.
Important Safety Warnings
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Age Restrictions: Never give promethazine to children under 2 years old. “Promethazine can cause severe breathing problems or death in a child in very young children.”
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Drowsiness: This medication causes severe drowsiness. Do not drive or operate dangerous machinery while taking it.
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Alcohol Interaction: Strictly avoid alcohol. It can dangerously intensify central nervous system depression
Side Effects
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Common: Daytime fatigue, dry mouth, dizziness, blurred vision, and vivid nightmares.
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Serious: Muscle stiffness, twitching/uncontrolled movements, irregular heartbeat, or a rare, fatal condition known as Neuroleptic Malignant Syndrome (NMS).
