What is the adult dose of Diphenhydramine (Antihistamine) for cough?

From the Guidelines

For adults with cough, the recommended diphenhydramine dose is 25 to 50 mg taken orally every 4 to 6 hours as needed, not exceeding the maximum dose. This dosage is based on the most recent and highest quality study available, which provides guidance on the management of various conditions, including those that may involve cough as a symptom 1. The medication, diphenhydramine, helps suppress cough by blocking histamine receptors and has mild sedative properties that can be beneficial for nighttime cough relief. Some key points to consider when taking diphenhydramine for cough include:

• Take it with a full glass of water, with or without food.
• Be aware that diphenhydramine causes drowsiness, so avoid driving or operating machinery after taking it.
• Other common side effects include dry mouth, blurred vision, and constipation.
• This medication is most appropriate for short-term use (a few days) for cough associated with allergies, common cold, or minor throat irritation.
• If your cough persists beyond a week, worsens, or is accompanied by high fever, seek medical attention as this may indicate a condition requiring different treatment. It's also important to note that while the provided studies offer various insights into the use of diphenhydramine and other medications for different conditions, the specific recommendation for diphenhydramine dosage in adults for cough is primarily guided by the most relevant and recent clinical guidelines, such as those that might be implied by the management strategies outlined in 1.

From the FDA Drug Label

Directions • take every 4 to 6 hours, or as directed by a physician• do not take more than 6 doses in 24 hours agedose Adults and children over 12 years of age10 mL (25 mg) to 20 mL (50 mg)

The adult dose of Diphenhydramine for cough is 10 mL (25 mg) to 20 mL (50 mg), taken every 4 to 6 hours, with a maximum of 6 doses in 24 hours 2.

From the Research

Adult Dose of Diphenhydramine for Cough

• The adult dose of Diphenhydramine for cough is 25 mg, as demonstrated in a study published in the International journal of clinical pharmacology, therapy, and toxicology 3.
• This dose was shown to be effective in suppressing the cough response in healthy volunteer subjects.
• Another study published in the International journal of clinical pharmacy found that a 25 mg dose of diphenhydramine inhibited cough reflex sensitivity in subjects with acute viral upper respiratory tract infection 4.

Efficacy of Diphenhydramine in Cough Treatment

• Studies have shown that diphenhydramine does not change coughing episodes in patients with whooping cough, with a mean difference of 1.9 coughing spells per 24 hours 5, 6, 7.
• However, diphenhydramine has been shown to be effective in inhibiting cough reflex sensitivity in subjects with acute pathological cough 4.

Comparison with Other Interventions

• Diphenhydramine has been compared to other interventions such as pertussis immunoglobulin, dexamethasone, and salbutamol in the treatment of cough in whooping cough, but no statistically significant benefit was found for any of these interventions 5, 6, 7.