Time Critical Medications
Article Last Updated:25/10/2025
Time-critical medications are drugs for which delayed or missed doses can lead to serious complications or worsening of the underlying condition.
No doses of a time-critical medication should be missed during a patient’s stay in the emergency department, and they should be given within 30 min of the usual administration time.
RCEM outlined 6 groups of time-critical medications, based on the mnemonic MISSED
| Time-critical medication group | Consequence of missed doses |
|---|---|
| Movement disorders – Parkinson’s disease and myasthenia gravis medications | Parkinson’s disease: risk of motor deterioration and neuroleptic malignant syndrome
Myasthenia gravis: risk of myasthenic crisis with respiratory compromise |
| Immunomodulators (including HIV medications) | Risk of disease flare-up, or viral resistance (in HIV) |
| Sugar – Insulin | Risk of DKA |
| Steroids (in adrenal insufficiency) | Risk of adrenal crisis |
| Epilepsy medications (anticonvulsants) | Risk of losing seizure control or status epilepticus |
| DOACs and warfarin | Risk of thromboembolic events (e.g. stroke, PE) |