Treatment outcome All Severe headache (VAS ≥ 4)
No. Percent No. incidence
Completed detoxification 198 52.2 75 0.38
Buprenorphine maintenance therapy 88 23.2 12 0.14
Methadone maintenance therapy 18 4.7 8 0.44
Drop out 75 19.8 32 0.43
Sum 379 100.0 127 0.34
Table 2: Incidence of severe headache (Visual analogue score of more than 3) in different outcomes of patients.