Intranasal medications, if understood and employed properly, are a great choice to avoid and IV or as a bridge until IV access is obtained.  Learn the strengths and limits of intranasal fentanyl, midazolam, ketamine, and dexmedetomidine.
Pain Management in Children
Traditionally, “brutaine”.
Goal: the “ouchless ED”. 
Two main barriers in pain treatment in children:
1. We consistently under-recognize children’s pain.  We may not detect the typical behaviors that children exhibit when they are in pain, especially in the pre-verbal child: crankiness or fussiness; changes in appetite or sleep; decreased activity; or physiologic findings such as dull eyes, flushed skin, rapid breathing, or sweating.2. We under-treat pain in children.  This is mostly from an old culture of misunderstanding or fear of overdose.
Four Components to Successful Pain Management and Intranasal Medication Administration
Right drug, right dose, right patient, right timing
Right Drug – Not every medication is easily amenable to intranasal administration.  We can use intranasal drugs for analgesia, for anxiolysis, for seizures – but not all drugs used for those purposes will perform well – or at all – via the IN route.
Right Dose – Dosing with IN meds will vary considerably from the IV route.  Rule of thumb:  the IN dose is 2-3 times the IV dose.
Right Patient – Is this patient and family appropriate for “just taking the edge off”?  What is the level of anxiety in the room?  How is the child relating to the parent, usually it’s the mother there.  What else is going on in that clinical snapshot as you walk in?
Right Timing – Mostly IV and IN onset times are very similar.  Notable exception:  intranasal midazolam may take 10-15 minutes to take effect – something to keep in mind when you plan your procedure.
Intranasal Medications bypass first-pass metabolism, and a portion of the drug is delivered into the CSF immediately via the nose-brain pathway.
Ideal Volume for Intranasal Medication: 0.25 to 0.3 mL per naris
Absolute maximum: 1 mL per naris (but expect some run-off)
Preload the device with 0.1 mL solution for dead space
Administer intranasal medications in the sniffing position.   Lie the patient flat with occiput posterior, put patient in the sniffing position, seat the mucosal atomizing device cushion in the naris, aim toward the pinna of the ear, and shoot fast – you have to push the drug as fast as you can to atomize the solution. 
Intranasal Fentanyl
Safe, effective at 2 mcg/kg.  Most commonly stocked concentration of fentanyl is 50 mcg/mL.  A 40-kg-child will reach the maximum volume possible for administration (40 kg x 2 mcg/kg = 80 mcg; at 50 mcg/mL – that makes 1.6 mL – if we divide the dose, it’s not ideal, but is still under our maximum of under 1 mL per naris.)  You graduate from intranasal fentanyl in elementary school.
Sufentanil for adults (half the volume of fentanyl) – 0.5 mcg/kg, which can be repeated as needed. 
Intranasal Midazolam
Intranasal Midazolam or versed for anxiolysis is dosed at 0.3 mg/kg (up to 0.5 mg/kg for procedural sedation)
Here, another practicality weighs in.  The IV preparation for midazolam is 5 mg/5 mL – this a very dilute solution.  You need to use the 5 mg/mL concentration to have any success with intransal midazolam because of the volume needed for the right effect.
A 20-kg-child will near the maximum volume for intranasal midazolam (0.3 mg/kg is 6 mg, at 5 mg/ml, 1.2 mL, or 036 mL per naris).  Kindergarten graduation is when to drop the intranasal midazolam.
Intranasal Ketamine
The IV dose for ketamine for pain control is 0.15 to 0.3 mg/kg, usually as an infusion over an hour.  The intranasal dose of ketamine for pain control is 1 mg/kg.Low-dose ketamine may be used for pain control as an adjunct and opioid-sparing agent.
Intranasal Dexmedetomidine
Dexmedetomidine is an alpha-2 receptor agonist, a smarter clonidine.  Clonidine is also an alpha-2 agonist, and it can cause a marked decrease in blood pressure with s