Table 1. Summary of anesthetic drugs used for pain relief during an emergency.

ppm: parts per million, IM: intramuscular, IV: intravenous, P.O: per oral, IN: intranasal, NSAIDs: non-steroidal anti-inflammatory drugs, ADHD: attention deficit hyperactivity disorder. 

Table data adapted from references [43-63].

Drug	Dose and Route of Administration	Onset of Action	Duration of Action	Indications	Contraindications	Side Effects
Ketamine [43-45]	IV (low dose for analgesia: 0.1 - 0.3 mg/kg).	within 30 seconds after injection.	5-10 minutes.	It is indicated as the single anesthetic drug used in surgical and diagnostic procedures that aren't needed for skeletal muscle relaxation. It is used for induction of anesthesia before administering further general anesthetics. It is used as a complement to low-potency drugs like nitrous oxide.	Ketamine hydrochloride is contraindicated in people who have demonstrated drug hypersensitivity or in whom a considerable increase in blood pressure would pose a serious risk.	Hypertension; Tachycardia; Respiratory depression; Apnea; Diplopia; Nystagmus; High intraocular pressure; Inflammatory urinary tract symptoms.
	IM (0.45 mg/kg)	within 3 to 4 minutes following injection.	12 to 25 minutes.
Fentanyl [46-50]	IV (50 - 100 mcg/kg/dose).	Almost Immediate	30-60 minutes	It is used for its short-duration analgesic action as needed in the recovery room during the first few hours after surgery. It is also used as a premedication. Anesthesiologists can use it for the induction and maintenance of anesthesia.	Patients who have experienced anaphylaxis or other fentanyl hypersensitivity are contraindicated to receiving fentanyl citrate injections.	Misuse, abuse, and addiction; Life-threatening respiratory depression; Serotonin syndrome; Cardiovascular depression; Gastrointestinal adverse reactions; Seizures.
	IM (50 - 100 mcg/kg/dose).	7-8 minutes	1-2 hours
	IN (1 - 2 mcg/kg/dose).	5-10 minutes	1 hour
	Nebulized (4 mcg/kg).	Almost Immediate	30-60 minutes
	Transmucosal lozenge( is available at various doses: 12, 25, 50, 75, and 100 mcg/h).	5-15 minutes	Related to blood level
Propofol [51-53]	IV (100-150 mcg/kg/min).	Within one minute.	5-10 minutes	Propofol is the most often used induction drug for general anesthesia. Propofol can be administered intermittently or continuously to maintain general anesthesia, providing precise control over the depth of anesthesia during the surgical operation.	It is contraindicated in cases of confirmed hypersensitivity, and allergy to eggs, soybeans, or soy.	Hypotension; Apnea lasts 30-60 seconds; Respiratory acidosis during weaning; Hypertriglyceridemia; Itching; Arrhythmia; Cardiac output decreased (concurrent opioid use increases incidence).
Lidocaine [54-55]	Intradermal injection (max recommended dose without epinephrine: 4.5 mg/kg, not to exceed 300 mg per dose).	1 to 3 minutes.	10 minutes	It is a local anesthetic agent that is indicated for the relief of pain.	It is contraindicated in individuals with a history of amide-type local anesthetic sensitivity.	Agitation; Flushing; Itching;  Blisters; Bruising; Burning feeling; Skin discoloration; Loss of pigmentation; Swelling; Exfoliation.
	Transdermal application (patches are available at doses of 700mg and 36mg).	3 to 5 minutes	11 hours (following application of 3 patches)
Morphine [47,56,57]	IV (50-100 mcg/kg/dose). IV Infusion: 10-20 mcg/kg/h.	5- 10 minutes	4-5 hours	It is used for the control of pain that cannot be adequately relieved by alternatives and that necessitates the intravenous injection of an opioid analgesic. The control of pain using intrathecal or epidural methods without the loss of sympathetic, sensory, or motor function.	Severe respiratory depression and acute or severe bronchial asthma. Concurrent use of monoamine oxidase inhibitors (MAOIs) or usage of MAOIs during the last 14 days. intestinal obstruction. Morphine hypersensitivity (such as anaphylaxis).	Dizziness; Drowsiness; Constipation; Nausea; Vomiting; Lightheadedness; Headache; Increased sweating; Urinary retention; Dry mouth.
	IM (50-100 mcg/kg/dose).	10-30 minutes	4-5 hours
	P.O (0.1-0.2 mg/kg/dose).	~30 minutes	3-5 hours
Nitrous oxide [47,58-60]	Inhalation (20 ppm).	2-5 minutes	N/A	In addition to treating severe pain, nitrous oxide can be utilized for dental anesthesia, procedural sedation, and general anesthesia. Because of its strong analgesic qualities, nitrous oxide can be helpful in analgesic environments like the emergency room or obstetrical ward.	Chronic obstructive pulmonary disease. Any history of having bleomycin. Nasal obstruction Claustrophobia Uncooperative behavior/cognitive impairment/psychiatric disorders.	Respiratory Depression; Diffusion hypoxia; Postoperative Nausea and Vomiting;  Hyperhomocysteinemia; Subacute myeloneuropathy.
Ibuprofen [61,62]	P.O (200 mg, 1 to 2 tablets every 4 to 6 hours while symptoms persist).	Within 30 minutes after ingestion.	4-6 hours	They are used as antipyretic, anti-inflammatory, and analgesic agents. These effects make NSAIDs useful for treating muscle pain during trauma. Topical NSAIDs are most useful for treating pain due to soft-tissue injuries. Parenteral NSAIDs can be administered as a non-opioid analgesic to manage pain and can also reduce fever.	NSAID hypersensitivity. Salicylate hypersensitivity. Patients who have undergone coronary artery bypass graft surgery. During the third trimester of pregnancy	Gastrointestinal problems' HTN Kidney damage; Allergic reactions.
	IV (400 to 800 mg, every 6)	Within minutes after the injection	4-6 hours
Aspirin [61,62]	for 325 mg tablets, 1 to 2 tablets every 4 hours, or 3 tablets every 6 hours.	Within 15- 30 minutes	4-6 hours
Naproxen sodium [61,62]	for 220 mg tablets, 1 to 2 tablets every 8 to 12 hours.	20 - 30 minutes	8 - 12 hours
Diclofenac sodium [61-62]	Topical solution (1.5%). The typical dose depends on the condition being treated.	1- 3 hours.	It takes around 6 - 12 hours, depending on the treated condition.
Clonidine [63]	Transdermal patch (0.1 mg/day, 0.2 mg/day, 0.3 mg/day).	Start to exert analgesic effect within a few days (2-3 days).	Up to 7 days.	Hypertension. Treatment of ADHD in children. Management of tics commonly found with Tourette syndrome. Adjunct therapy for severing cancer-related pain. As an adjunct in neonatal opioid withdrawal syndrome.	Drug hypersensitivity. Pregnancy. There is an absolute drug interaction contraindication but there are some drugs that require caution during their concomitant use.	Abdominal pain; Headache; Hypotension; Fatigue; Nausea; Emotional instability; Constipation; Xerostomia; Diarrhea; Sexual dysfunction; Dizziness; Sedation
	P.O (0.1 mg).	30 - 60 minutes	6 - 12 hours
	Epidural infusion (30 mcg/hr).	15-30 minutes after the initiation of infusion.	6-12 hours with continuous infusion.