Diphenhydramine
Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.
| ID | DRUG-DIPHENHYDRAMINE |
|---|---|
| Type | Drug |
| Aliases | BenadrylDimedrolДифенгідрамін |
| Status | reviewed 2026-04-27 | pending_clinical_signoff |
| Diseases | None declared |
| Sources | SRC-NCCN-BCELL-2025 SRC-NCCN-MM-2025 |
Drug Facts
| Class | First-generation H1 antihistamine (ethanolamine class); also moderate anticholinergic, sedative-hypnotic, antiemetic, mild α1-blocker |
|---|---|
| Mechanism | Competitive reversible H1 receptor antagonist that blocks histamine- mediated vasodilation, increased capillary permeability, smooth- muscle contraction, sensory nerve stimulation, and pruritus. Lipophilic — readily crosses the blood-brain barrier producing significant sedation. Additional actions: muscarinic antagonism (anticholinergic — dry mouth, urinary retention, mydriasis, constipation, confusion in elderly), modest α1-adrenergic antagonism (mild orthostatic hypotension), and 5-HT-antagonist / D2-antagonist effects contributing to antiemetic and antimotion- sickness activity. In oncology supportive care, used as: (1) premedication for chemotherapy infusion reactions (paclitaxel, carboplatin retreatment, rituximab, monoclonal antibodies); (2) adjunct treatment of mild-to-moderate hypersensitivity / infusion reactions (mainstay of pruritus, urticaria, mild bronchospasm — but NOT a s... |
| Typical dosing | PREMEDICATION (paclitaxel, rituximab, etc.): 25-50 mg IV 30 min before infusion (paired with H2 antagonist + dexamethasone). ACUTE INFUSION REACTION / mild anaphylaxis adjunct: 25-50 mg IV push, may repeat every 4-6 h (max 400 mg/day adult). Acute extrapyramidal reaction: 25-50 mg IV/IM push, repeat in 15-30 min if no response. Allergic urticaria / pruritus: 25-50 mg PO every 4-6 h, max 300 mg/day. Pediatric: 1 mg/kg IV/PO q6h (max 50 mg per dose, 300 mg/day). Geriatric (≥65 yrs): use cautiously — start 25 mg, increased fall and confusion risk; consider non- sedating second-generation H1 (cetirizine, loratadine) for non-emergency indications. Renal impairment: extended dosing interval (q9h... |
| Ukraine registered | True |
| NSZU reimbursed | True |
| Ukraine last verified | 2026-04-27 |
Notes
Foundation H1 antihistamine for chemotherapy infusion-reaction premedication (especially paclitaxel — Cremophor vehicle reactions — and rituximab / other monoclonal antibodies). Standard premedication package: dexamethasone 20 mg IV + diphenhydramine 25-50 mg IV + H2 antagonist (famotidine 20 mg IV) given 30 min before chemo. Also first adjunct for ACTIVE infusion reactions (urticaria, pruritus, mild bronchospasm, mild flushing) — but ESCALATE TO EPINEPHRINE if hypotension, severe bronchospasm, upper airway edema, or no response to antihistamine + steroid + fluids within 10-15 min. CRITICAL: diphenhydramine is NEVER a substitute for epinephrine in anaphylaxis — the leading cause of preventable fatal anaphylaxis is using antihistamine alone. Beers-list inappropriate in elderly (≥65 yrs) for routine use due to anticholinergic delirium and fall risk — substitute non-sedating second-generation H1 for chronic indications. Extrapyramidal reaction rescue: 25-50 mg IV reverses metoclopramide / promethazine acute dystonia within 5-10 min. Ukraine: cheap, ubiquitous.
Used By
No reverse references found in the YAML corpus.