Use with caution only when no safe alternative is available, and benefit outweighs acute attack risk.
In a life threatening emergency, do not withhold any critically required medication.
In an emergency do not delay, however if time permits, find a safe alternative.
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Assess risk vs. benefit |
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Highest risk in patients with
- Recurrent attacks
- Recent attacks
- Other triggers present, e.g. fasting, alcohol, multiple medications
- Females of reproductive age
Lower risk in patients with
- Asymptomatic acute porphyria
- Latent acute porphyria
(Note that low risk doesn't mean no risk) |
Expected benefit from treatment? |
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If benefit outweighs risk, treat but take precautions. |
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Counsel patient
- On risk vs. benefits
- To avoid other triggers: fasting, alcohol, recreational drugs.
- Regarding acute attack symptoms like severe abdominal/back/leg pain and, possibly behavioural change; this may be accompanied by nausea, vomiting, constipation, but these are also known adverse drug effects.
- On actions to take if symptoms were to develop.
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Prepare
- Measure baseline urine porphobilinogen (PBG), since baseline concentrations may be elevated.
- Establish availability of haemin to treat a potential future attack.
- Inform all healthcare professionals involved in patient’s care.
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Manage
- If symptoms develop, stop drug and repeat urine PBG urgently, and compare to baseline for interpretation.
- Manage confirmed acute attacks.
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