From the Guidelines
Hydroxychloroquine can cause gastrointestinal side effects, including nausea, vomiting, abdominal pain, and diarrhea, in some patients, as reported in a 2020 study published in Gastroenterology 1. These side effects are generally infrequent and may be managed with proper administration, such as taking the medication with food or milk.
- The typical dosing for hydroxychloroquine is not explicitly stated for COVID-19 treatment in the provided evidence, but it is FDA-approved for other indications.
- Starting with a lower dose and gradually increasing it may help reduce gastrointestinal distress, although the optimal dosing strategy is still under investigation.
- If gastrointestinal symptoms persist, patients should consult their healthcare provider, as dose adjustments or alternative medications may be necessary, considering the potential for cardiac conduction defects and liver injury associated with hydroxychloroquine use 1.
- It is essential to exercise caution in patients with hepatitis or other hepatic diseases, as hydroxychloroquine is known to concentrate in the liver, and may trigger hypersensitivity reactions in certain individuals, as noted in the 2020 Gastroenterology study 1.
From the FDA Drug Label
Gastrointestinal Disorders Nausea, vomiting, diarrhea, and abdominal pain. The answer to the question about Hydroxychloroquine GI bleeds is that GI bleeds are not directly mentioned in the drug label as an adverse reaction. However, gastrointestinal disorders such as nausea, vomiting, diarrhea, and abdominal pain are listed.
- Key points:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain 2
From the Research
Hydroxychloroquine Side Effects
- Hydroxychloroquine (HCQ) and chloroquine (CQ) are known to induce adverse effects which may reduce their use and effectiveness in the therapy of autoimmune disorders 3.
- The occurrence of ocular adverse reactions can be minimised by close attention to the dose (which should be set on a body weight basis) with regular (e.g. quarterly) retinal examination 4.
- HCQ has a lower incidence of gastrointestinal adverse reactions compared with CQ and it might have a lower risk of ocular adverse reactions 4.
- The strong binding to melanin reflects the ocular injury and dermatological properties of these drugs 4.
Hydroxychloroquine Benefits
- HCQ has been used extensively for systemic lupus erythematosus (SLE) where it has a good reputation for controlling the dermatological complications in SLE 4.
- HCQ is effective in reducing disease progression or exacerbations and/or the use and dosage of corticosteroids in autoimmune disorders 3.
- HCQ may reduce atherosclerosis and risks of cardiovascular disease in rheumatic patients 4.
- HCQ has been shown to improve glycaemia and reduce the risks of type II diabetes mellitus 4.
Hydroxychloroquine Mechanism of Action
- The modes of action of HCQ in autoimmune disorders represent somewhat of an enigma, but it is known to accumulate in lysosomes and autophagosomes of phagocytic cells, affecting MHC Class II expression and antigen presentation 4, 5.
- HCQ also affects the production of pro-inflammatory cytokines, control of toll-like receptor-9 activation, and leucocyte generation of reactive oxygen species (ROS) 4, 5.
- The exact relationships of these various actions have not been specifically defined in vivo or ex vivo in relation to clinical efficacy 4.