Emergency warning: In anaphylaxis with breathing difficulty, wheeze, throat/tongue swelling, hypotension, collapse, or rapidly worsening symptoms, IM adrenaline (epinephrine) is first-line. Hydrocortisone and Avil do not act quickly enough to replace adrenaline. Tintinalli's Emergency Medicine, Table 14-4.

1. Hydrocortisone sodium succinate injection

Mechanism

• A corticosteroid with glucocorticoid and some mineralocorticoid activity.
• Enters cells and changes gene transcription, reducing inflammatory cytokines, capillary permeability, and late-phase allergic inflammation.
• Its clinical anti-inflammatory effect is not immediate. It is an adjunct in allergy/anaphylaxis, not rescue treatment for airway obstruction or shock.

Common indications

• Acute adrenal crisis or suspected adrenal insufficiency
• Severe acute asthma/COPD exacerbation
• Severe allergic reaction or anaphylaxis, after adrenaline
• Acute inflammatory/autoimmune disease flare, where prescribed
• Prevention/treatment of some infusion or drug hypersensitivity reactions

Contraindications

• Known hypersensitivity to hydrocortisone or formulation components
• Systemic fungal infection
• Do not give intrathecally or epidurally. Serious neurologic injury has been reported.
• IM corticosteroid preparations are contraindicated in idiopathic thrombocytopenic purpura.

How it is commonly given

• Routes: slow IV injection, IV infusion, or deep IM injection.
• In acute emergency care, IV is commonly used when IV access is present.
• The dose depends entirely on the diagnosis, severity, patient age/weight, comorbidities, and local protocol.
• A commonly used adult adjunct dose in severe allergic reactions is hydrocortisone 100-200 mg IV, but this is not a universal dose or replacement for a patient-specific order.

Reconstitution and dilution

1. Use aseptic technique.
2. Reconstitute with not more than 2 mL sterile/bacteriostatic water for injection or bacteriostatic sodium chloride, as specified by that vial's manufacturer.
3. This typically gives approximately 50 mg/mL.
4. For slow IV injection or IM injection, further dilution is usually not necessary after correct reconstitution.
5. For IV infusion, the reconstituted solution may be added to 50-1000 mL compatible fluid such as 0.9% saline or 5% dextrose, depending on fluid needs and local policy.

Side effects

• Increased blood glucose
• Increased BP, fluid and sodium retention
• Dyspepsia, nausea
• Mood change, agitation, insomnia
• Transient high WBC count
• Injection-site pain or infection risk if asepsis is poor
• Rare: hypersensitivity reaction, arrhythmia, severe hypertension

• Increased infection risk and masking of infection
• Gastritis/ulcer/GI bleeding
• Muscle weakness, osteoporosis
• Cushingoid changes, weight gain
• Adrenal suppression if stopped abruptly after prolonged use
• Cataract/glaucoma

2. Avil injection: Pheniramine maleate

Mechanism

• A first-generation H1 antihistamine.
• Blocks histamine at H1 receptors, reducing itching, urticaria, flushing, rhinorrhea, and some angioedema symptoms.
• It has anticholinergic and sedative effects because it crosses the blood-brain barrier.
• It does not reliably reverse hypotension, bronchospasm, or upper-airway obstruction in anaphylaxis.

Common indications

• Acute urticaria and itching
• Allergic rash or drug-related allergic symptoms
• Allergic rhinitis/conjunctival symptoms, in selected situations
• Adjunct after adrenaline in anaphylaxis, mainly for skin symptoms

Contraindications and precautions

• Known allergy to pheniramine/other antihistamines or excipients
• Neonates and very young infants, according to the local product label
• Angle-closure glaucoma
• Urinary retention, bladder-neck obstruction, or significant prostatic enlargement
• Severe respiratory depression
• Concomitant alcohol, opioids, benzodiazepines, or other sedatives
• Driving/operating machinery after administration

How it is commonly given

• Route is usually slow IV or deep IM, depending on the exact local product label and clinical situation.
• In India, Avil ampoules are commonly labelled pheniramine maleate 22.75 mg/mL. Confirm the ampoule concentration before drawing it up.
• A commonly used adult emergency dose is pheniramine 22.75 mg slow IV or IM, but the prescriber must determine the actual dose and pediatric dosing.

• Give slowly, with the patient monitored for excessive sedation, dizziness, hypotension, and paradoxical agitation.
• Keep the patient supine if unwell and reassess airway, breathing, oxygen saturation, pulse, and BP.
• Never give it as a rapid IV push.

Dilution

• If your local product permits IV administration, it may be given slowly IV as per the product label or hospital protocol.
• If dilution is required by your protocol, use a compatible diluent such as 0.9% saline and administer slowly.
• Do not mix it in the same syringe with hydrocortisone unless a compatibility reference specifically approves it.

Side effects

• Drowsiness/sedation, dizziness, reduced alertness
• Dry mouth, blurred vision
• Nausea, constipation
• Urinary retention
• Tachycardia or palpitations
• Hypotension, especially if given rapidly IV
• Confusion or delirium, especially in older adults
• Paradoxical excitation, especially in children
• Rare: seizures, arrhythmias, severe allergic reaction

Practical allergy/anaphylaxis sequence

1. Assess ABCs, call for help, place patient supine if hypotensive, give oxygen as indicated.
2. If anaphylaxis is suspected: IM adrenaline first in the anterolateral thigh.
3. Establish IV access, monitor BP, pulse, SpO₂, ECG when indicated, and give IV fluids if hypotensive.
4. Avil/pheniramine: adjunct for hives/itching.
5. Hydrocortisone: adjunct for delayed inflammatory effects or as clinically indicated.
6. Observe for recurrence and document the suspected trigger.

Safe administration reminders

Easy Chart: Hydrocortisone and Avil with Symptoms

Simple symptom-to-drug memory

Easy side-effect chart

Easy safety points