Yes, you can take Sudafed (pseudoephedrine) and Delsym (dextromethorphan) together
These two medications can be safely combined for most patients, as they work through different mechanisms—pseudoephedrine as a nasal decongestant and dextromethorphan as a cough suppressant—and this combination is commonly found in over-the-counter cold preparations. 1
Key Safety Considerations
Generally Safe Combination
The combination of pseudoephedrine and dextromethorphan is widely used and appears in numerous commercial cold/cough preparations. Research specifically examining this combination found it to be generally well-tolerated with minimal adverse events 2. A recent 2024 study demonstrated efficacy and safety of combination products containing dextromethorphan with decongestants for treating cough associated with common cold 3.
Important Warnings and Contraindications
Avoid this combination if you:
- Are taking or have recently taken (within 14 days) MAO inhibitors (monoamine oxidase inhibitors), as dextromethorphan can contribute to serotonin syndrome when combined with MAOIs 4
- Are taking other serotonergic medications (SSRIs, SNRIs, other antidepressants), as dextromethorphan is listed among cough/cold medications requiring caution 4
- Have uncontrolled hypertension, hyperthyroidism, glaucoma, coronary artery disease, cerebrovascular disease, or bladder neck obstruction—pseudoephedrine should be used with extreme caution in these conditions 5
Use With Caution If You Have:
- Controlled hypertension: Pseudoephedrine causes small increases in systolic blood pressure (0.99 mmHg) and heart rate (2.83 beats/min), though generally well-tolerated. Monitor blood pressure due to individual variation 5
- Cardiac conditions: Pseudoephedrine can cause palpitations, elevated blood pressure, and increased heart rate 5
- Are taking stimulant medications (e.g., for ADHD): Concomitant use may increase adverse effects additively 5
Age-Specific Considerations
Children under 6 years: Exercise extreme caution. Oral decongestants in young children have been associated with serious adverse events including agitated psychosis, ataxia, hallucinations, and even death 5. A case report documented a 2-year-old developing hyperirritability, psychosis, and ataxia after overmedication with pseudoephedrine/dextromethorphan combination 6.
Children over 6 years and adults: Generally well-tolerated when used at appropriate doses 5
Dosing Recommendations
- Start treatment within the first 2 days of cold symptoms for maximum efficacy 7
- Use recommended doses only—do not exceed package instructions
- Be aware that dextromethorphan abuse occurs among adolescents at megadoses (5-10 times recommended dose), which can produce PCP-like effects 8
Common Side Effects to Monitor
From pseudoephedrine: Insomnia, loss of appetite, irritability, tremor, palpitations 5
From dextromethorphan: Generally well-tolerated at therapeutic doses; serious effects only occur with overdose or in the ~5% of people who lack normal metabolism 8
Bottom Line
This is a safe and commonly used combination for treating concurrent nasal congestion and cough in most healthy adults and children over 6 years. However, absolutely avoid if taking MAOIs or other serotonergic drugs, and use with careful monitoring if you have cardiovascular disease or hypertension.