Letter to the Editor - Fibromyositis after Intramuscular Pentazocine Abuse

A 22-year-old male presented with a two year history of Pentazocine use, which was prescribed to him for abdominal pain. He was taking 25mg of Promethazine and 30mg of Pentazocine mixed in the same syringe intramuscularly, at first into the gluteus and deltoid regions alternately; and later into the quadriceps muscles exclusively because of ease of administration. He always used disposable syringes, but without any local antisepsis. The initial frequency of use of once a week increased to every alternate day with evidence of tolerance, craving and withdrawal. Four months prior to admission, the patient developed swelling and pain in the muscle at first, followed by difficulty in bending his knees, squatting and walking. During this time the patient would inject to reduce the pain in his thighs.