| DRUG | ADVERSE EFFECT | PATIENTS WHO EXPERIENCED EFFECT (%) |
| Amitriptyline* | Constipation | 14 |
| Dizziness | 28 | |
| Dry mouth | 90 | |
| Somnolence | 66 | |
| Capsaicin cream (Zostrix) | Cough | 8 |
| Skin irritation | 54 | |
| Duloxetine (Cymbalta) | Constipation | 9 |
| Diarrhea | 6 | |
| Fatigue | 9 | |
| Headache | 10 | |
| Nasopharyngitis | 6 | |
| Nausea | 22 | |
| Somnolence | 8 | |
| Sweating | 6 | |
| Gabapentin (Neurontin) | Confusion | 7 |
| Diarrhea | 10 | |
| Dizziness | 24 | |
| Headache | 10 | |
| Nausea | 8 | |
| Somnolence | 20 | |
| Lidocaine 5% patch (Lidoderm) | No adverse effects significantly different from placebo | — |
| Opiates | Constipation | 33 |
| Dizziness | 21 | |
| Nausea | 33 | |
| Somnolence | 29 | |
| Vomiting | 15 | |
| Pregabalin (Lyrica)† | Dizziness | 7 to 28 |
| Edema | 6 to 16 | |
| Somnolence | 5 to 13 | |
| Weight gain | 4 to 9 | |
| Tramadol (Ultram) | Constipation | 22 |
| Headache | 17 | |
| Nausea | 23 | |
| Somnolence | 12 |