What is the recommended dilution ratio for Avil (pheniramine maleate) injection?

Avil (Pheniramine Maleate) Injection Dilution

For intravenous administration of pheniramine maleate (diphenhydramine equivalent), dilute to 1-2 mg/kg (maximum 50 mg) in 10 mL of 0.9% sodium chloride or 5% dextrose and administer slowly over 2-5 minutes to avoid pain at the IV site and prevent seizures. 1

Dosing and Dilution Protocol

Standard IV/IM Dosing

• Dose: 1-2 mg/kg per dose (maximum initial dose: 50 mg) 1
• Route preference: IM route is acceptable; IV route requires dilution and slow administration 1

IV Dilution Technique

• Dilute the calculated dose in 10 mL of 0.9% sodium chloride 1
• Alternative diluent: 5% dextrose (D5W) can be used 1
• Administer over 2-5 minutes minimum to prevent adverse effects 1

Critical Safety Warnings

Rapid IV administration carries significant risks:

• May precipitate seizures if given too rapidly 1
• Can cause hypotension, especially when combined with other sedative agents 1
• May cause respiratory suppression and apnea, particularly with concurrent sedatives 1
• Risk of paradoxical excitement or agitation at all doses 1

Clinical Context for Use

In anaphylaxis management:

• Pheniramine maleate (like diphenhydramine) is second-line therapy only after epinephrine 1
• Should never be administered alone in anaphylaxis treatment 1
• Combination with H2-blockers (ranitidine 1 mg/kg diluted in 20 mL D5W over 5 minutes) is superior to H1-antihistamine alone 1

For acute hypersensitivity reactions:

• Standard dose remains 1-2 mg/kg IV/IM (maximum 50 mg) 1
• Monitor oxygen saturation and respiratory effort continuously 1
• Be prepared to support ventilation 1

Pediatric Considerations

Age-specific restrictions:

• Avoid in children under 6 years for routine allergic symptoms due to 33 reported deaths between 1969-2006 2
• If used in emergency situations (anaphylaxis) in children over 6 years, use lower end of dosing range (1 mg/kg) 2
• Liquid formulations are absorbed more rapidly than tablets in acute reactions 2

Common Pitfalls to Avoid

1. Never give undiluted IV push - always dilute in at least 10 mL of compatible solution 1
2. Never administer rapidly - minimum 2 minutes infusion time to prevent seizures 1
3. Never use as monotherapy in anaphylaxis - epinephrine must be given first 1
4. Monitor for respiratory depression - especially critical when combined with benzodiazepines or opioids 1