Neuropathic Pain Drugs PDF

Neuropathic Pain Drugs Dr Mashael Al-Mutairi MLS [email protected] Pain – Nociceptive pain results from the activation of pain receptors: Radicular Pain: This occurs when nerve roots are irritated, leading to sensations down the arm or leg. Somatic Pain: occurs when pain receptors in tissu...

Neuropathic Pain Drugs Dr Mashael Al-Mutairi MLS [email protected] Pain – Nociceptive pain results from the activation of pain receptors: Radicular Pain: This occurs when nerve roots are irritated, leading to sensations down the arm or leg. Somatic Pain: occurs when pain receptors in tissues (such as muscles, bones, or skin) are stimulated.. Visceral Pain: Results from injury or inflammation in internal organs (e.g., involuntary muscles in the heart). It’s often described as aching and may have a vague location. -Neuropathic pain result from dysfunction in the nervous system. damage Caused by: Nerve Injury: Due to conditions as diabetes, shingles, or trauma. or such Diseases: Like multiple sclerosis, HIV, or cancer. Medications: Some medications like chemotherapy drugs can cause nerve damage and subsequent pain. Other Factors: Spinal cord compression, and inflammation. injuries, nerve Signs and the symptoms connected to the presence of neuropathic pain are: – Allodynia (pain due to a stimulus that does not normally provoke pain) – Hyperalgesia (an increase in the perception of pain generated by a stimulus that causes pain) – Paresthesia (Pins and needles). Neuropathic pain management focuses on treating symptoms, and only in some pathological condition, the etiological causes can be treated relieving pain. First-line Second-line  Tricyclic antidepressants Topical Analgesic  Capsaicin 8% patches  Anticonvulsant (Gabapentin and pregabalin)  Lidocaine (lignocaine) patches  SNRI (Serotonin noradrenaline reuptake inhibitors)– Duloxetine, Venlafaxine Third-line  Strong opioids (oxycodone, Tramadol) Tricyclic antidepressants (TCAs) First-line  Efficient in the treatment of painful neuropathy, nerve injury pain, postherpetic neuralgia, central postpartum pain, and in the treatment of pain following spinal cord injury.  Amitriptyline achieved their effects by inhibiting serotonin and noradrenaline reuptake from the presynaptic terminals as well as inhibiting effects on cholinergic, adrenergic, and histaminergic receptors and ionic channels.  TCAs are contraindicated in patients with: – Some cardiac conduction disturbances – Patients with glaucoma – Patients with prostate hypertrophy Anti-convulsant Gabapentin and Pregabalin  Similar structure to the gamma-aminobutyric acid neurotransmitter, they bind to the (α2-δ subunit) of Ca²+ voltage-dependent channels reducing Ca²+ influx to the cells.  Both have obtained excellent responses in the treatment of diabetic pain, herpetic neuralgia, Spinal cord injury, and phantom limb syndrome.  Side effects: dizziness, sedation and ataxia Serotonin Noradrenaline Reuptake Inhibitors (SNRIs)  Inhibit the reuptake of serotonin norepinephrine at the synaptic level. and  Duloxetine is the most effective in reducing neuropathic pain.  Duloxetine and venlafaxine are associated with increased blood pressure and cardiac conduction abnormalities and therefore should be used cautiously in patients with cardiac disease. Second-line Lidocaine and Capsaicin  Recommended for neuropathic pain. patients with peripheral  Lidocaine patches blocking voltage-gated sodium channels locally reduce spontaneous ectopic nerve discharge. Capsaicin is a potent receptor agonist (transient receptor potential cation channel subfamily V member 1 also known as vanilloid receptor 1 (TRPV1)). TRPV1 sensitive to different ranges of temperature and probably are responsible for range of temperature sensation. Capsaicin molecule produces the same sensation that excessive heat or abrasive damage would cause Third-line Tramadol  A µ-opioid agonist, centrally acting synthetic opioid medication, but also exerts effects that may contribute to its analgesic properties in neuropathic pain including:  Serotonin inhibition. and norepinephrine reuptake  Used in the management of moderate to moderately severe pain Oxycodone and morphine stimulates opioid receptors in the brain. Does not eliminate the sensation of pain but decreases discomfort by increasing the tolerance to pain. also causes sedation and depression of respiration.  Prescribed for the management of pain severe enough to require daily, around-the-clock, longterm treatment with a narcotic, and for which alternative treatment options are inadequate for the relief of moderate to severe pain.