Neuropathic Pain

Question 1

what is neuropathic pain?

Answer 1

Neuropathic pain is caused by damage or injury to the nerves that transfer information between the brain and spinal cord from the skin, muscles and other parts of the body

Question 2

what is allodynia?

Answer 2

Allodynia is the experience of pain from stimuli that isn’t normally painful.

Question 3

2 classes of drugs used to treat neuropathic pain?

Answer 3

tricyclic antidepressants and certain anti-epileptic drugs

Question 4

which tricyclic antidepressant is used to treat neuropathic pain?

Answer 4

amitriptyline hydrochloride.

Question 5

anti-epileptics used to treat neuropathic pain?

Answer 5

pregabalin and gabapentin

Question 6

Can Nortriptyline be used for neuropathic pain?

Answer 6

YES, it may be better tolerated than amitriptyline hydrochloride. (unlicensed indication - nortriptyline)

Question 7

Neuropathic pain may respond to which opioid analgesics?

Answer 7

Tramadol hydrochloride can be prescribed when other treatments have been unsuccessful, while the patient is waiting for assessment by a specialist.

Question 8

Can you give morphine and oxycodone for neuropathic pain?

Answer 8

YES should be initiated only under specialist supervision

Question 9

what topical local anaesthetic preparations can be given to neuropathic pain?

Answer 9

YES, lidocaine medicated plasters can be prescribed while awaiting specialist review.

Question 10

can capsaicin 0.075% cream be used for neuropathic pain?

Answer 10

YES. Capsaicin 0.075% cream is licensed for the symptomatic relief of postherpetic neuralgia.

Question 11

can capsaicin 8% cream be used for neuropathic pain?

Answer 11

A self-adhesive patch containing capsaicin 8% is licensed for the treatment of peripheral neuropathic pain. It should be used under specialist supervision.

Question 12

what is post-herpetic neuralgia?

Answer 12

Postherpetic neuralgia is a painful condition that affects the nerve fibers and skin. It is a complication of shingles, and shingles is a complication of chicken pox. If the pain caused by shingles continues after the bout of shingles is over, it is known as post-herpetic neuralgia (PHN)

Question 13

what is Trigeminal neuralgia?

Answer 13

Trigeminal neuralgia is a chronic pain condition that affects the trigeminal nerve, which carries sensation from your face to your brain. If you have trigeminal neuralgia, even mild stimulation of your face — such as from brushing your teeth or putting on makeup — may trigger a jolt of excruciating pain.

Question 14

which drug can be given to treat Trigeminal neuralgia?

Answer 14

carbamazepine

Question 15

what is the dosage of amitriptyline to treat neuropathic pain? BNF

Answer 15

Initially 10–25 mg daily, dose to be taken in the evening, then increased, if tolerated, in steps of 10–25 mg every 3–7 days in 1–2 divided doses; usual dose 25–75 mg daily, dose to be taken in the evening, doses above 100 mg should be used with caution (doses above 75 mg should be used with caution in the elderly and in patients with cardiovascular disease); maximum per dose 75 mg.

Question 16

what is mode of action of amitriptyline?

Answer 16

Amitriptyline is a tricyclic antidepressant (TCA) which inhibits neuronal reuptake of serotonin and noradrenaline from the synapse in the central nervous system; this increases their availability in the synapse to cause neurotransmission on the post-synaptic neurone.

Question 17

what are the most common side effects of amitriptyline?

Answer 17

Anticholinergic syndrome; drowsiness; QT interval prolongation

Question 18

what is Anticholinergic syndrome?

Answer 18

Anticholinergic syndrome results from competitive antagonism of acetylcholine at central and peripheral muscarinic receptors. Central inhibition leads to an agitated (hyperactive) delirium - typically including confusion, restlessness and picking at imaginary objects - which characterises this toxidrome. Peripheral inhibition is variable - but the symptoms may include: hot, dry skin, flushed appearance, mydriasis, tachycardia, decreased bowel sounds and urinary retention.

Question 19

Treatment cessation of amitriptyline?

Answer 19

Withdrawal effects may occur within 5 days of stopping treatment with antidepressant drugs; they are usually mild and self-limiting, but in some cases may be severe. The risk of withdrawal symptoms is increased if the antidepressant is stopped suddenly after regular administration for 8 weeks or more. The dose should preferably be reduced gradually over about 4 weeks, or longer if withdrawal symptoms emerge (6 months in patients who have been on long-term maintenance treatment).

Question 20

can amitriptyline be used in hepatic impairment?

Answer 20

Manufacturer advises use with caution in mild-to-moderate hepatic impairment; avoid in severe impairment.

Question 21

how to treat overdose of amitriptyline?

Answer 21

Activated charcoal given within 1 hour of the overdose reduces absorption of the drug.

Question 22

what are the side effects of overdose of Tricyclic antidepressants?

Answer 22

dry mouth, coma of varying degree, hypotension, hypothermia, hyperreflexia, extensor plantar responses, convulsions, respiratory failure, cardiac conduction defects, and arrhythmias. Dilated pupils and urinary retention also occur.

Question 23

what are the Cautionary and advisory labels for amitriptyline tablets and solution?

Answer 23

Label 2 - Warning: This medicine may make you sleepy. If this happens, do not drive or use tools or machines. Do not drink alcohol

Question 24

what is the mode of action of carbamazepine?

Answer 24

Carbamazepine is a sodium channel blocker. It binds preferentially to voltage-gated sodium channels in their inactive conformation, which prevents repetitive and sustained firing of an action potential.

Question 25

what is the dosage of carbamazepine to treat Trigeminal neuralgia? (immediate-release medicines)

Answer 25

For Adult By mouth using immediate-release medicines
Initially 100 mg 1–2 times a day, some patients may require higher initial dose, increase gradually according to response; usual dose 200 mg 3–4 times a day, increased if necessary up to 1.6 g daily.

Question 26

what is the dosage of carbamazepine to treat Trigeminal neuralgia? (modified release preparation)

Answer 26

By mouth modified release tablets

For Adult
Initially 100–200 mg daily in 2 divided doses, some patients may require higher initial dose. After initial dose, increase according to response; usual dose 600–800 mg daily in 2 divided doses, increased if necessary up to 1.6 g daily in 2 divided doses, dose should be increased slowly.

Question 27

what are the license restrictions on the use of carbamazepine?

Answer 27

carbamazepine is not licensed for use in trigeminal neuralgia in children

Question 28

what are the cautions for carbamazepine use?

Answer 28

Cardiac disease; history of haematological reactions to other drugs; may exacerbate absence and myoclonic seizures; skin reactions; susceptibility to angle-closure glaucoma

Question 29

in which instances carbamazepine should be withdrawn immediately?

Answer 29

carbamazepine should be withdrawn immediately in cases of aggravated liver dysfunction or acute liver disease. Leucopenia that is severe, progressive, or associated with clinical symptoms requires withdrawal (if necessary under cover of a suitable alternative).

Question 30

common side effects of carbamazepine?

Answer 30

Dizziness; drowsiness; dry mouth; eosinophilia; fatigue; fluid imbalance; gastrointestinal discomfort; headache; hyponatraemia; leucopenia; movement disorders; nausea; oedema; skin reactions; thrombocytopenia; vision disorders; vomiting; weight increased

Question 31

what are the most common side effects of carbamazepine at the start of treatment and in the elderly?

Answer 31

Some side-effects (such as headache, ataxia, drowsiness, nausea, vomiting, blurring of vision, dizziness and allergic skin reactions) are dose-related, and may be dose-limiting. These side-effects are more common at the start of treatment and in the elderly.

Question 32

what are the monitoring requirements for carbamazepine?

Answer 32

Manufacturer recommends blood counts and hepatic and renal function tests (but evidence of practical value uncertain).

Question 33

which side effects of carbamazepine patients and their carers should be able to recognise?

Answer 33

Patients or their carers should be told how to recognise signs of blood, liver, or skin disorders, and advised to seek immediate medical attention if symptoms such as fever, rash, mouth ulcers, bruising, or bleeding develop.

Question 34

what are the Cautionary and advisory labels of carbamazepine for immediate release tablets, suppositories, solution?

Answer 34

Label 3 - Warning: This medicine may make you sleepy. If this happens, do not drive or use tools or machines
Label 8 - Warning: Do not stop taking this medicine unless your doctor tells you to stop

Question 35

what are the Cautionary and advisory labels of carbamazepine for modified release tablets?

Answer 35

Label 3 - Warning: This medicine may make you sleepy. If this happens, do not drive or use tools or machines
Label 8 - Warning: Do not stop taking this medicine unless your doctor tells you to stop
Label 25 - Swallow this medicine whole. Do not chew or crush

Question 36

can carbamazepine be used in renal and hepatic impairment?

Answer 36

use with caution and close monitoring

Question 37

explain Anti-epileptic hypersensitivity syndrome with carbamazepine

Answer 37

Antiepileptic hypersensitivity syndrome associated with carbamazepine.
Caution—cross-sensitivity reported with oxcarbazepine and with phenytoin.