Hi, thanks for posting your concern in the HCM. Firstly, Amitriptyline is a tricyclic antidepressant. It has several side effects. Commoner are headache, nausea, dizziness, weight gain and anticholinergic symptoms (dry mouth, blurring of vision, urinary hesitancy, constipation etc.). Anxiety, agitation, confusion, insomnia, hallucination, mania, hypomania, seizure, numbness, burning pain, tingling, sinus tachycardia, chest pain, heaviness in chest, arrythmia, T-wave inversion, conduction disorder, gynaecomastia, galactorrhoea, impotence, loss of libido may occur less commonly. Rare but serious side effects include, increased suicidal tendencies, neuroleptic malignant syndrome, cardiomyopathy, MI, Heart block, hepatitis, liver failure, thrombocytopenia, agranulocytosis, eosinophilia, allergic reactions and anaphylaxis etc. Secondly, I think you should have a proper evaluation of your low back pain. Low back pain can definitely arise from depression or anxiety disorder. But, prior to considering that, any spinal abnormality, bony pathology, muscle sore, diseases involving pelvic viscera, kidney etc. should be ruled out. It may be necessary to have blood tests, urine examination and imaging done to come to a diagnosis. For the time being you can have OTC analgesic (e.g. PCM 500 mg SOS, min. 6 hr interval should be maintained) and /or muscle relaxants (Cyclobenzaprine 15 mg or Thiocolchicoside 4 mg) to have symptomatic relief from pain. An orthopedic consultation will be necessary. If you have any sleep cycle disorder, please consult a psychiatrist. Amitryptiline should not be taken without consulting a psychiatrist for any sleep problem. For any further query, please write back to us. Regards. Dr. Kaushik