What it's for (Indications)
- Dextromethorphan hydrobromide + diphenhydramine combination formulations are primarily indicated for the temporary symptomatic relief of cough and other associated symptoms commonly encountered with the common cold or upper respiratory allergies.
- Specifically, dextromethorphan, an antitussive, is employed to suppress non-productive coughs originating from minor throat and bronchial irritation.
- Diphenhydramine, a first-generation antihistamine, addresses symptoms such as sneezing, rhinorrhea (runny nose), watery eyes, and itching of the nose or throat, which are often co-occurring allergic manifestations or cold symptoms.
- Furthermore, diphenhydramine's sedative properties may offer relief for sleep disturbance caused by persistent coughing or congestion, particularly beneficial for nighttime symptom management.
- This combination aims to provide comprehensive relief from multiple disruptive symptoms of acute respiratory illnesses.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | Dosage should be individualized based on age, weight, and specific product formulation. Typically, for adults, dextromethorphan 10-30 mg and diphenhydramine 25-50 mg every 4-6 hours, not to exceed maximum daily doses. Always consult the product label for specific dosing instructions. |
Safety & Warnings
Common Side Effects
- The use of dextromethorphan hydrobromide + diphenhydramine can lead to a range of side effects, primarily due to the anticholinergic and sedative properties of diphenhydramine.
- Common side effects include significant drowsiness, sedation, dizziness, impaired coordination, and blurred vision, which can affect the ability to operate machinery or drive safely.
- Anticholinergic effects such as dry mouth, dry eyes, urinary retention, and constipation are also frequently reported.
- Less common but potentially more serious side effects may include paradoxical excitation, particularly in pediatric patients, tachycardia, palpitations, hypotension, and, in rare instances or with overdose, central nervous system depression, hallucinations, or seizures.
- Gastrointestinal disturbances like nausea, vomiting, and abdominal discomfort may also occur.
- Patients should be advised to monitor for any severe or persistent adverse reactions and seek medical attention if necessary, especially if experiencing difficulty breathing, severe dizziness, or significant changes in heart rate.
Serious Warnings
- Black Box Warning: **Serious Warnings: Risk of Central Nervous System (CNS) Depression, Serotonin Syndrome, and Abuse Potential.** This medication, containing dextromethorphan and diphenhydramine, carries significant risks. Profound CNS depression, including severe sedation, respiratory depression, coma, and death, may occur, especially with concomitant use of alcohol, opioids, benzodiazepines, or other CNS depressants. Patients should be warned against operating heavy machinery or driving while taking this medication. There is a serious risk of Serotonin Syndrome when dextromethorphan is co-administered with monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), or other drugs that affect serotonergic neurotransmitter systems. Symptoms include mental status changes (e.g., agitation, hallucinations), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination), and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Furthermore, both dextromethorphan and diphenhydramine have known potential for abuse and misuse, which can lead to severe adverse events, including psychosis, seizures, cardiac arrhythmias, coma, and death. Prescribers should assess the patient's risk of abuse prior to prescribing and monitor during treatment. Diphenhydramine's anticholinergic effects also pose risks in susceptible populations such as the elderly or those with underlying anticholinergic-sensitive conditions.
- Pregnant and lactating females should consult their doctors before taking this medication.
- Use with caution in patients with known hypersensitivity/allergies to the components, and in patients with emphysema.
How it Works (Mechanism of Action)
Dextromethorphan acts centrally on the cough center in the medulla to suppress cough. Diphenhydramine is an antihistamine (H1-receptor blocker) with anticholinergic and sedative properties, which can further aid in cough suppression and alleviate associated symptoms.
Commercial Brands (Alternatives)
No other brands found for this formula.