Adult Dose of Chlorpheniramine Maleate Intramuscular Injection for Cold
The recommended adult dose of chlorpheniramine maleate for cold symptoms via intramuscular injection is 10 mg. 1
Dosing Guidelines
Chlorpheniramine maleate is a first-generation H1 antihistamine commonly used to treat symptoms associated with the common cold, such as sneezing, rhinorrhea, and nasal congestion. When administered via the intramuscular route for adults with cold symptoms, the following dosing applies:
- Adult dose (>12 years): 10 mg IM 1
- Administration can be done as a single dose or divided throughout the day depending on symptom severity
- Duration of action is approximately 4-6 hours
Clinical Considerations
Efficacy for Cold Symptoms
Antihistamines like chlorpheniramine have shown limited short-term beneficial effects on cold symptoms:
- Most effective during the first 1-2 days of treatment 2
- Primarily helps with symptoms like rhinorrhea and sneezing
- Less effective for nasal congestion
- No significant effect on the overall duration of the common cold 2
Combination Therapy
Chlorpheniramine is often used in combination with other medications for cold symptoms:
- Fixed-dose combinations with paracetamol and phenylephrine have shown efficacy in reducing total symptom scores in adults with common cold 3
- The standard oral dose in such combinations is typically 2 mg 3
Safety Considerations
Adverse Effects
When administering chlorpheniramine via IM injection, be aware of these potential adverse effects:
- Sedation (most common)
- Drowsiness
- Dizziness
- Dry mouth
- Blurred vision
- Urinary retention
Contraindications and Precautions
Exercise caution when administering to patients with:
- Narrow-angle glaucoma
- Prostatic hypertrophy
- Urinary retention
- Severe hypertension or coronary artery disease
- Hyperthyroidism
- History of antihistamine hypersensitivity (rare but reported) 4
Special Populations
Elderly Patients
- Increased risk of adverse effects, particularly anticholinergic effects and sedation
- Consider starting with a lower dose if necessary
Pregnancy
- Chlorphenamine is often chosen by clinicians due to its long safety record when antihistamine therapy is necessary during pregnancy 1
Alternative Routes of Administration
If IM administration is not feasible or preferred, consider:
- Oral administration: 4 mg every 4-6 hours (not to exceed 24 mg in 24 hours)
- IV administration: Same as IM dosing (10 mg), administered slowly
Clinical Pearl
While chlorpheniramine can help manage cold symptoms, it's important to note that antihistamines alone have limited efficacy for the common cold. The Cochrane review found that antihistamines have only a modest short-term effect on symptom severity and no clinically significant effect on nasal obstruction 2.