This document presents an overview of adjuvant analgesics or co-analgesics, emphasizing their role in enhancing pain management, particularly for neuropathic pain and other types less responsive to opioids. It details various medications, their dosing guidelines, potential side effects, and the importance of patient-specific treatment plans. The responsibilities of healthcare providers in determining appropriate treatments and the risks associated with these medications are also highlighted.

1. Adjuvants or Co-analgesics
Disclaimer: This presentation contains information on the general principles of pain management. This presentation cannot account for
individual variation among patients and cannot be considered inclusive of all proper methods of care or exclusive of other treatments. It
is the responsibility of the treating physician, or health care provider, to determine the best course of treatment for the patient. Treat the
Pain and its partners assume no responsibility for any injury or damage to persons or property arising out of or related to any use of
these materials, or for any errors or omissions.

2. Objectives
• Review different forms of adjuvant or co-analgesic medication
• Understand adult dosing for each
• Learn when to utilize them
• Review potential side effects
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3. Adjuvant analgesics or co-analgesics
Adjuvant analgesics, which are also referred to as co-analgesics,
are medicines that are not primarily used for analgesia. These
are medicines that are administered alone or with NSAIDs and
opioids that may:
• Enhance the analgesic activity of the NSAIDs or opioids
• Have independent analgesic activity for certain pain types
(such as neuropathic pain)
• May counteract the side effects of NSAIDs or opioids
Beating Pain, 2nd Ed. APCA (2012); Using Opioids to Manage Pain, APCA (2010) 3

4. Principles in adjuvant therapy
• The use of adjuvants that target neuropathic pain may be
particularly important because such pain may be difficult to
treat with opioids alone
• Adjuvants are also useful for other pains that are only partially
sensitive to opioids such as bone pain, smooth or skeletal
muscle spasms, or pain related to anxiety
Beating Pain, 2nd Ed. APCA (2012); Using Opioids to Manage Pain, APCA (2010) 4

5. Antidepressants
Used for neuropathic pain, presenting primarily as burning or
abnormal sensations (dysaesthesia)
• Amitriptyline
– Adults: 10-75mg or 0.5-2mg/kg at night then increase
slowly as needed
– Commonly start at 12.5mg at night and then increase to
twice per day as needed
– Response should be evident within 5 days
• If no effect after 1 week, stop the drug
Beating Pain, 2nd Ed. APCA (2012); Using Opioids to Manage Pain, APCA (2010); Introductory Palliative Care Course for Health Care
Professionals (Uganda). PCAU/MOH (2013).
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6. Antidepressants
– Side-effects include dry mouth and drowsiness
– Use with caution in the elderly because it may increase
falls
– Use with caution in those with cardiac disease because it
may cause orthostatic hypertension
• Nortriptyline
– May be better tolerated than amitryptyline
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Beating Pain, 2nd Ed. APCA (2012); Using Opioids to Manage Pain, APCA (2010); Introductory Palliative Care Course for Health Care
Professionals (Uganda). PCAU/MOH (2013).

7. Anticonvulsants
Use for neuropathic pain; check for drug interactions
• Clonazepam
– Adults: 0.5mg to 2mg once a day
• Carbamazepine
– Adults: start at 100mg twice a day and can be increased up to 800mg twice a day
• Sodium valproate
– Adults: 200 mg - 1.2g once a day
• Gabapentin
– Adults: start with 300mg at bedtime and titrate up every 2 or 3 days (300mg twice
per day, then three times per day) until effective or side effects occur
– Usual effective dose is 300-600mg three times a day (maximum dose 1200mg
three times per day)
– Decrease dose in patients with renal insufficiency
Beating Pain, 2nd Ed. APCA (2012); Palliative Care for HIV/AIDS and Cancer Patients in Vietnam, Basic Training Curriculum: Harvard
Medical School, Centre for Palliative Care (2007); Oxford Textbook of Palliative Medicine (2010) 7

8. Anticonvulsants
• Use Phenytoin and Carbamazepine with caution because of
the rapid metabolism of other drugs metabolised in the liver
and therefore potential drug interactions
• Side effects: drowsiness, loss of muscle coordination (ataxia)
or blurring of vision
Beating Pain, 2nd Ed. APCA (2012) 8

9. Antispasmodics
Use antispasmodics for muscle spasm, e.g. colicky abdominal
pain or renal colic
• Hyoscine butylbromide (Buscopan)
– Adults: start at 10mg three times a day; can be increased
to 40mg three times a day
• Antispasmodics can cause nausea, dry mouth, or constipation
Beating Pain, 2nd Ed. APCA (2012) 9

10. Muscle relaxants
Use these drugs for skeletal muscle spasm and anxiety-related
pain
• Diazepam
– Adults: 5mg orally 2 or 3 times a day
• Lorazepam
– 0.5-2mg oral or intravenous every 3 to 6 hours
• Side effects: can cause drowsiness and ataxia
Beating Pain, 2nd Ed. APCA (2012); Oxford Textbook of Palliative Medicine. (2010) 10

11. Corticosteroids
Use corticosteroids for bone pain, neuropathic pain, headache due to raised
intracranial pressure, and pain associated with oedema and inflammation
• Dexamethasone
– Adults: 2–4mg per day for most situations
– For raised intracranial pressure, start at 24mg per day and reduce by 2mg each day to
the lowest effective maintenance dose
– For pain from nerve compression, start at 8mg
– For spinal cord compression, start at 16mg
• Prednisolone
– Use when dexamethasone is not available
– A conversion rate of 4mg Dexamethasone to 30mg Prednisolone can be used
Beating Pain, 2nd Ed. APCA (2012) 11

12. Corticosteroids
• In advanced disease, a corticosteroid may improve
appetite, decrease nausea and malaise, and improve
quality of life
• Side effects include neuropsychiatric syndromes,
gastrointestinal disturbances and immunosuppression
• When stopping a corticosteroid, remember gradually
taper down the dose
Beating Pain, 2nd Ed. APCA (2012) 12

13. Bisphosphonates
Bisphosphonates are used for the treatment of cancer-related
bone pain
• Pamidronate- 60-90mg slow intravenous infusion every 4
weeks
• Side effects
– Fever and flu-like weakness
– Osteonecrosis of the jaw, although rare, has been
associated with bisphosphonate therapy
Beating Pain, 2nd Ed. APCA (2012) 13

14. Take home messages
• Co-analgesics are important complementary medications in
pain relief
• Used with the correct combinations, co-analgesics can
enhance analgesic effects
• Adjuvants are useful for neuropathic pain and other pains that
are only partially sensitive to opioids such as bone pain,
smooth or skeletal muscle spasms, or pain related to anxiety
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15. References
• African Palliative Care Association. Beating Pain: a pocketguide for pain
management in Africa, 2nd Ed. [Internet]. 2012. Available from:
http://www.africanpalliativecare.org/images/stories/pdf/beating_pain.pdf
• African Palliative Care Association. Using opioids to manage pain: a pocket guide
for health professionals in Africa [Internet]. 2010. Available from:
http://www.africanpalliativecare.org/images/stories/pdf/using_opiods.pdf
• Amery J, editor. Children’s Palliative Care in Africa [Internet]. 2009. Available from:
http://www.icpcn.org/wp-content/uploads/2013/08/Childrens-Palliative-Care-in-
Africa-Full-Text.pdf
• Kopf A, Patel N, editors. Guide to Pain Management in Low-Resource Settings
[Internet]. 2010. Available from: http://www.iasp-
pain.org/files/Content/ContentFolders/Publications2/FreeBooks/Guide_to_Pain_
Management_in_Low-Resource_Settings.pdf
• The Palliative Care Association of Uganda and the Uganda Ministry of Health.
Introductory Palliative Care Course for Healthcare Professionals. 2013.
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