Pharmacology for Pain

Medication	Indications for pain	Dose range	Notes
Carbamazepine	First line for Trigeminal Neuralgia	Start at 100 mg BID and increase to 1200 mg/day	Blood tests (baseline and follow up) Genetic screening (HLA*B1502) Contraindicated in heart disease. Careful: Steven Johnson Syndrome. Careful: Endocrine hormones decrease. Carbamazepine is associated with dose-limiting side effects, particularly with prolonged usage. Therapeutic level is 4.
Oxcarbazepine	Trigeminal Neuralgia	Start with 150 mg BID; increase to 1800 mg	Blood test (Sodium). Genetic screening (HLA*B1502). 10-OH-carbazepine metabolite (therapeutic level 15).
Gabapentinoids (Gabapentin) (Note: also for SUNA).	Peripheral Neuropathies, headache preventive, widespread muscle pain.	Start 100-300 hs; by 300 mg q 3rd day to a max of 3600 mg/day	Gabapentin interacts with a high-affinity binding site in brain membranes, voltage-sensitive Ca2+ channels. Caution with kidney disorders. Caution with BP and water retention.. Do not give with opioids
Gabapentinoids (Pregabalin)	Peripheral Neuropathies, headache preventive, widespread muscle pain.	Start 25 mg TID; increase to 100-200 TID (max dose: 600 mg)	Approved for fibromyalgia. Pregabalin inhibits presynaptic excitatory neurotransmitter release by blocking α2δ calcium channels. Caution with kidney disorders. Caution with BP. Do not give with opioids. Weight gain.
Divalproex/sodium valproate / Valproic acid (Note: for migraine prophylaxis).	Trigeminal Neuralgia, headache preventive.	250mg 2xday; 500-1000mg/day	Weight gain.
Topiramate (Note: Chronic migraine – SUNC & SUNA – Hemicrania continua).	Trigeminal Neuralgia, headache preventive.	Start 15-25 mg/hs; increase to a max of 200mg/day in divided doses (BID)	Blood test (bicarbonate level). Caution: acidosis and kidney stones. Side Effects: Cognitive impairment and Weight loss.
Lamotrigine (Lamictal) (Note: SUNC - TN).	Trigeminal Neuralgia, headache preventive.	25mg/day BID increased gradually to maintenance doses of 200-400mg/d.	Careful: Steven Johnson Syndrome. Pertinent serum levels of concurrent anticonvulsants and liver function testing, and renal function assessments. But, there is no indication for routine monitoring of lamotrigine levels unless there is evidence of ineffectiveness, poor adherence or toxicity.
Clonidine (Note: SMP). Antihypertensive. Modifies the adrenergic component of pain. Alpha 2 agonist. Imidazoline receptor agonist.	CRPS, adjuvant for Trigeminal Neuralgia, preventive for headaches.	0.1-0.2 mg bid. Do not exceed 2.4mg per day. It is available as patches, tablets, injectables, and topical compounds.	Careful: Postural hypotension. Clonidine has multiple off-label uses, such as managing withdrawal symptoms from opioids, benzodiazepines, and alcohol, and for treatment of anxiety, insomnia, and post-traumatic stress disorder (PTSD). It has been used to control hot flashes in menopause, for restless leg syndrome, and prophylaxis of vascular migraine headaches.
Nortriptyline (TCA) All TCAs: Inhibit reuptake of 5-HT and NE. Block sodium channels. Show affinity for NMDA. Block alpha-adrenergic. Block H1. Block acetylcholine. Enhance opioid receptors.	All chronic pain conditions where modulation is impaired. Myogenous pain, preventive for headaches, neuropathies.	Start 10 mg; increase to 50-70 mg	Note: EKG in patients over 40. Contraindicated (all TCAs): Glaucoma, urinary retention, prostatic hypertrophy. impaired liver function, CV disease.
Amitriptyline (TCA) All TCAs: Inhibit reuptake of 5-HT and NE. Block sodium channels. Show affinity for NMDA. Block alpha-adrenergic. Block H1. Block acetylcholine. Enhance opioid receptors Show affinity for NMDA. Block alpha-adrenergic. Block H1. Block acetylcholine. Enhance opioid receptors.	All chronic pain conditions where modulation is impaired. Myogenous pain, preventive for headaches, neuropathies.	Start 10 mg Max dose is 75 mg per day	Note: EKG in patients over 40. Contraindicated (all TCAs): Glaucoma, urinary retention, prostatic hypertrophy. impaired liver function, CV disease.
Desipramine (TCA) All TCAs: Inhibit reuptake of 5-HT and NE. Block sodium channels. Show affinity for NMDA. Block alpha-adrenergic. Block H1. Block acetylcholine. Enhance opioid receptors.	All chronic pain conditions where modulation is impaired. Myogenous pain, preventive for headaches, neuropathies.	Start 25 mg daily and increase up to 150 mg.	Note: EKG in patients over 40. Contraindicated (all TCAs): Glaucoma, urinary retention, prostatic hypertrophy. impaired liver function, CV disease.
Trazodone (TCA) Inhibits 5-HT2 receptors. Increases total sleep time and stage 3	All chronic pain conditions where modulation is impaired. Myogenous pain, preventive for headaches, neuropathies. When sleep is impaired.	150 mg orally per day in divided doses, up to 600 mg.	Common trazodone side effects may include: drowsiness, dizziness, tiredness, swelling, weight loss, blurred vision, diarrhea, constipation, stuffy nose.
Cyclobenzaprine (Flexeril)	Muscle spasm.	10mg taken at bedtime (can be increased to tid). Duration of action of 12-24 hours and elimination half-life of 1-3 days.	Skeletal muscle relaxant related with amitriptyline. Anticholinergic side effects. Cyclobenzaprine appears to exert its effects in the midbrain and the spinal level and has a wider margin of safety than most of the other centrally acting muscle relaxant drugs. Contraindicated in chronic heart failure, conduction disorders of the heart, the recovery phase following myocardial infarct as well as narrow-angle glaucoma, seizures, and prostate hypertrophy. Not recommended in elderly patients because of its prolonged half-life and increased plasma levels.
Duloxetine	Chronic pain conditions where modulation is impaired.	Start 20 mg at bedtime; increase to max of 60-120 mg/day	Serotonin and noradrenaline reuptake inhibitor Diabetic neuropathy, Fibromyalgia.
Baclofen (for muscle spasticity)	Muscle spasm. Coadjutant in Trigeminal Neuralgia.	Start at 5 mg TID; increase by 5mg q 2-3 days to a max of 80 mg/day	Gaba B agonist Withdrawal effects: HAT (hallucinations, anxiety, and tachycardia) Off-label: decreasing alcohol cravings and alcohol-related anxiety, trigeminal neuralgia, gastroesophageal reflux disease, and hiccups.
Clonazepam (Note: BMS).	Burning Mouth Syndrome. Trigeminal Neuralgia.	Start 0.25 mg TID; increase slowly to a maximum of 3 mg/day for BMS
Indomethacin (Indo-test is with 100 mg)	Trigeminal Autonomic Cephalalgias.	25 mg TID, may go up to 75 or more TID	Gastric bleeding Cross brain blood barrier Inhibits Nitric oxide
Sumatriptan (5‑HT1B and 5‑HT1D receptors) (Sumatriptan test is with 25mg PO, repeat if no relief in 20 mins)	Migraine Headache.	Nasal: 5mg or 20mg sprayed in the ipsilateral nostril at onset; may repeat once after 2 hours. FAST ACTING BUT LOW BIOAVAILABILITY SC: 1-6 mg SC; max is 6 mg/dose up to 12 mg over 24 hrs, may repeat dose once. FOR RAPID ONSET PO: 25-100 mg PO x1, may repeat 1x after 2 hr (max 200 mg)	Contraindicated in CV patients Produce serotonin syndrome (also TCA) Avoid if the patient is taking Saint Johns Wort Agonist of B (blood-vasoconstriction) and D (neurogenic inflammation)
Rizatriptan (5‑HT1B and 5‑HT1D receptors)	Migraine Headache.	5-10 mg.
Naratriptan (5‑HT1B and 5‑HT1D receptors) (for long-lasting attacks and previous adverse effects)	Migraine Headache.	1-2.5 mg PO; max 5 mg, may repeat once after 4 h
Frovatriptan for long-lasting attacks and previous adverse effects (for long-lasting attacks – menstrual migraine)	Migraine Headache.	2.5 mg
Lasmiditan (selective 5-HT1F – for acute migraine attack) The 5-HT_1F receptor is found on terminals and cell bodies of trigeminal ganglion neurons and can modulate the release of CGRP from these nerves.	Migraine Headache.	50mg, 100mg, 200mg Once as needed NO repeat dose	No driving. Treatment-related side effects seem to be related to the rapid penetration of the drug into the brain and include dizziness, paresthesia, and drowsiness, mostly of mild to moderate intensity. Serotonin-1F receptor (5-HT1F) agonists relieve acute migraine without vasoconstriction.
Propranolol (Note: migraine prophylaxis).	Preventive for headaches.	40 mg up to 160-240 mg (PO divided doses).	Do not give if: Asthma, Raynaud, depression Myasthenia gravis CV conditions
Verapamil (Note: cluster prophylaxis).	Preventive for Cluster headache.	240mg/d taken in 3 divided doses- max dose 480mg/d.	Causes: Hypotension Side effect: Constipation, gingival hyperplasia Dizziness, nausea, or tiredness may occur.
Ubrogepant (Note: migraine abortive).	Acute migraine.	50 mg or 100 mg PO once, repeat dose 2 hours PRN, max 200 mg/day	Can be used in CV patients Careful: Liver/kidney disease
Rimegepant (Note: migraine abortive).	Acute migraine.	75mg ODT Single-dose, no-repeat Max monthly =15 migraine attacks/month	Can be used in CV patients Careful: Liver/kidney disease
Atogepant	Acute migraine.	60mg
Erenumab (Monoclonal antibodies) (Note: migraine prophylaxis).	Preventive for migraine.	Self-inject once a month 70 mg or 140 mg SC	Caution: 6 months before pregnancy
Galcanezumab (Monoclonal antibodies) (Note: migraine/ cluster prophylaxis).	Preventive for migraine.	Loading dose 240 mg SC; followed by monthly injections of 120 mg SC For episodic cluster prevention: 300 mg SC (3 injections) every 30 days while having an active cluster cycle	Caution: 6 months before pregnancy
Metoclopramide (Note: migraine with vomiting).	Acute for migraine with vomiting.	10 mg/4-8 hr orally	Caution with triptans (serotonin syndrome) Extrapyramidal effects
Botulinum Toxin A	Persistent muscle pain. Neuropathic pain.	Masseter 15-40 (20) units Temporalis 10-30 (25) units Lateral Pterygoid 5-30 (15) units Anterior Digastric 10 units For neuralgia: 5units subcutaneously in trigger zones. For migraine: (155 in 31 sites)
Oxygen (Note: for cluster).	Acute Cluster headache.	7-15 L per minute for 15-20 min
Prednisone	Acute pain. Giant Cell arteritis.	60mg/day for 5 days, then taper by 10 mg/day for the next 5 days
Acetazolamide (Note: primary cough headache, Increased intracranial hypertension).	Exertion headaches.	Dose: 375 in divided dosages up to 2200mg/day
Valtrex	Viral infection.	Dose. 500mg tabs, bid for 3-5 days. (oral infection), If HSV1 2g bid for 1 day Bell’s palsy 1g 3xday for 7 days plus Prednisone 60mg daily for 5 days followed by 10mg less each day for 5 days or Prednisone 50mg for 10 days. Acyclovir for Bell’s palsy is 400mg, (5xday) equaling 2000mg/day for 10 days.
Zolpidem (non-benzodiazepine) Hypnotic Insomnia treatment	Sleep related disorders.		GABAA receptor agonist. It works by increasing GABA effects in the central nervous system by binding to GABAA receptors at the same location as benzodiazepines.

¶ Frequently prescribed medications for pain management:

¶ Frequently used topical medications:

¶ Neuropathic Pain

¶ Muscle or joint pain