Hydroxychloroquine is pretty well tolerated from what I’ve seen (never seen chloroquine given we have a safer alternative). The most common side effect is nausea/vomiting/diarrhoea and this is the only thing I could find a rate on (~10%). There are also a collection of rare, severe side effects.
Some of my concerns are:
Most of our safety data would be targeted at use in relatively well patients with rheumatological or dermatological disease, not acutely unwell infective patients (I have no idea about its safety profile in malaria other than it’s not really used anymore due to resistance)
Unknown dosage—as you suggested a lower dose might be safer but could also be below the therapeutic dose (the studies DO seem to use a fairly high dose)
The chloroquines come with a risk of QT prolongation; coronavirus comes with a risk of myocarditis—I would expect one would have much higher rates of arrhythmias. Also worsened by the other QT prolonging medication one would be on by then (azithromycin), and electrolyte abnormalities present in critical illness/from GI side effects of the drugs and infection. Admittedly, myocarditis seems to be a late development and the patient would be in ICU already, rather than early in the disease
Most of this probably comes down to the unknown—this is extremely early days into the investigation of using hydroxychloroquine for COVID19. I don’t think we know enough about this to be using it outside of the medical setting. Maybe my risk threshold would be for its earlier use in those over 60 or those with isolated hypertension? I’m unsure. This could all change within 1-2 weeks as I’d expect there’ll be significantly more data.
Hydroxychloroquine is pretty well tolerated from what I’ve seen (never seen chloroquine given we have a safer alternative). The most common side effect is nausea/vomiting/diarrhoea and this is the only thing I could find a rate on (~10%). There are also a collection of rare, severe side effects.
Some of my concerns are:
Most of our safety data would be targeted at use in relatively well patients with rheumatological or dermatological disease, not acutely unwell infective patients (I have no idea about its safety profile in malaria other than it’s not really used anymore due to resistance)
Unknown dosage—as you suggested a lower dose might be safer but could also be below the therapeutic dose (the studies DO seem to use a fairly high dose)
The chloroquines come with a risk of QT prolongation; coronavirus comes with a risk of myocarditis—I would expect one would have much higher rates of arrhythmias. Also worsened by the other QT prolonging medication one would be on by then (azithromycin), and electrolyte abnormalities present in critical illness/from GI side effects of the drugs and infection. Admittedly, myocarditis seems to be a late development and the patient would be in ICU already, rather than early in the disease
Most of this probably comes down to the unknown—this is extremely early days into the investigation of using hydroxychloroquine for COVID19. I don’t think we know enough about this to be using it outside of the medical setting. Maybe my risk threshold would be for its earlier use in those over 60 or those with isolated hypertension? I’m unsure. This could all change within 1-2 weeks as I’d expect there’ll be significantly more data.