Fitness to work after medication and poor sleep
A driver is due to book on at 21:40 for a 10-hour night shift. At 13:00, feeling hay fever symptoms, the driver took 50 mg of diphenhydramine, a sedating antihistamine. The driver slept only four hours the previous night and now feels groggy, with a mild fever of 37.8°C. A colleague offers to swap the shift informally so the driver can go home. The driver has no other symptoms and believes the medication 'has probably worn off'. The roster is already short-staffed, and the driver does not want to cause disruption. The driver must decide whether to book on and what to tell the manager.
1. Assess the driver's fitness to work and explain the relevant factors.
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The driver is not fit to work. Diphenhydramine is a sedating antihistamine, and although it was taken 8 hours and 40 minutes before booking on, its effects can persist and are likely to be worse when combined with only four hours' sleep and a mild fever. The driver's own feeling of grogginess is a warning sign. Night shifts increase sleep pressure, and the driver will be responsible for safety-critical decisions over a long period. The fact that the medication 'has probably worn off' is not a reliable assessment; the driver should not self-certify fitness when impaired. The safe decision is to declare unfit before booking on, not after starting the shift.
2. What should the driver do about the shift and the informal swap?
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The driver should tell the roster manager or supervisor before booking on that they are unfit for safety-critical duty, stating that they have taken a sedating medication, have had insufficient sleep, and have a fever. The driver should not arrange an informal swap with a colleague without management approval, because the roster manager must confirm that the replacement is competent for the shift, within hours limits, and that the swap is recorded. An informal swap can leave gaps in fatigue management and leave the driver's fitness status unrecorded. The driver should follow the company's absence and fitness-to-work procedure, seek medical advice if symptoms persist, and not return to duty until fit.
3. What should the manager do with the information, and how should confidentiality be handled?
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The manager should treat the information as confidential medical information and share it only with those who need it to manage the roster and the driver's return to work. The manager should record the driver as unfit, arrange cover, and make sure the driver is not pressured to work because the roster is short-staffed. The manager should not discuss the driver's medication or sleep problems with colleagues who do not need to know. If the driver later returns, the manager should check whether any restrictions apply and whether a fitness-for-duty assessment is needed. The driver's willingness to declare unfitness should be treated as a safety-positive action, not a disciplinary matter.