Hydroxychloroquine, “An Extremely Safe Drug”


“Chloroquine and especially HCQ are considered very safe medications.” – Ronald F. van Vollenhaven, “Systemic Lupus Erythematosus: Which Drugs and When?” 

“If it is taken in proper doses, chloroquine is an extraordinarily safe drug.” – Ilan Ben-Zvi, et al. “Hydroxychloroquine: From Malaria to Autoimmunity”

“Antimalarial medications are extremely safe…” – Patient fact sheet, Rheumatic Dermatology Society


Hydroxychloroquine’s safety is clearly reflected in pre-pandemic guidance issued by U.S. and global health agencies, including the W.H.O. and CDC, which stated: “Hydroxychloroquine can be prescribed to adults and children of all ages. It can also be safely taken by pregnant women and nursing mothers… Hydroxychloroquine is a relatively well tolerated medicine.”

Like most drugs, HCQ has potential side effects. The most common ones, gastrointestinal disturbances, are largely minor. Some are dangerous but extremely uncommon. The most potentially serious side effect associated with HCQ is QT prolongation, a change in the heart muscle’s electrical signaling system. This change raises the risk of “torsades de pointes,” a very rare abnormal heart rhythm which can result in sudden death. QT prolongation is itself a temporary, reversible side effect experienced by about 10% of patients; if the prolongation is sufficiently severe, some of these may need to stop taking the drug. However, if there is an indication to do so, QT prolongation is easily detected with appropriate monitoring by EKG, and doesn’t preclude use of the drug on an outpatient (non- hospitalized) basis. Small amounts of QT prolongation are considered allowable and are the most common form of this change, when the change is seen at all. HCQ’s degree of QT prolongation puts it in the midrange of 30 commonly used drugs. Some major drug classes, such as fluoroquinolones, result in far more pronounced QT prolongation than HCQ but are still widely used.

The essential safety of chloroquine and HCQ is reflected in the vast scale of the drugs’ historic usage, with tens of billions of doses consumed by many hundreds of millions of people over seven decades. These were mostly for the treatment of malaria and virtually all outside the hospital setting and without screening EKGs. From 1978-1988 world consumption of chloroquine exceeded 3,000 metric tons, equal to about 14 billion doses over that decade alone. In 2005 it was estimated that annual consumption of chloroquine for treatment of malaria was still in the range of 300-500 million courses per year, despite the rise of chloroquine-resistant malaria. In the U.S. alone from 2008-2018, patients received around 55.2 million prescriptions for HCQ. This includes some 1.5 million people living with autoimmune diseases like lupus or rheumatoid arthritis, who are typically prescribed two 200 mg pills daily for a period lasting years.

By all accounts the incidence of torsades de pointes resulting from heart arrhythmia is extremely low. In over seven decades of use, there have been a handful of reports of fatal arrhythmias due to torsades de pointes from all drug causes, and zero reports of fatal arrhythmias with HCQ use. Other side effects, such as retinopathy and kidney damage, result only from years of long-term use and have been described as “rare.”

The pre-pandemic medical consensus on the safety of HCQ is summarized in this advice for patients, published by the Rheumatoid Arthritis Support Network in 2018:

“Like all medications, there is the risk of side effects. Fortunately, the problems seen by people taking this medication are usually very mild. Serious side effects are rare. Overall, most people who have any noticeable side effects from hydroxychloroquine experience diarrhea or nausea. These usually get better after the person adjusts to the medication, and taking the drug with food can help, as well. Additionally, some people experience anemia and vision changes or even vision loss, but this is quite rare. It’s more commonly seen with high doses for long periods, in older people, and in those who have kidney problems.”

Regarding the safety of hydroxychloroquine in COVID-19 patients specifically, a study in the European Society of Cardiology’s journal, EP Europace found that short-term treatment was not associated with severe cardiac rhythm disorders in patients with COVID-19 under appropriate surveillance. The study concluded: “HCQ administration is safe for a short-term treatment for patients with COVID-19 infection regardless of the clinical setting of delivery, causing only modest QTc prolongation and no directly attributable arrhythmic deaths.”


Ivermectin, “Astonishingly Safe For Human Use”


“Ivermectin has continually proved to be astonishingly safe for human use.” – Crump, Andy, and Satoshi Omura, “Ivermectin, ‘Wonder drug’ from Japan: the human use perspective”

“Ivermectin is an antiparasitic drug with a broad spectrum of activity, high efficacy as well as a wide margin of safety.” AB Canga et al., “The Pharmacokinetics and Interactions of Ivermectin in Humans A Mini-review”

“After more than 25 years of use, ivermectin continues to provide a high margin of safety for a growing number of indications based on its anti-parasitic and anti-inflammatory activities.” – Kircik LH et al., “Over 25 Years of Clinical Experience With Ivermectin: An Overview of Safety for an Increasing Number of Indications”


No serious medical or scientific authority has ever questioned the safety of ivermectin, which has been widely used for decades in low and middle-income countries for the treatment of parasitic diseases such as onchocerciasis (“river blindness”) and lymphatic filariasis, and in developed countries for the treatment of roundworms, scabies, and severe head lice infestations. Since its introduction for human use in the 1980s, around 3.7 billion doses of ivermectin have been distributed in global public health campaigns with only a small number of adverse effects reported, likely due to extremely rare occurrences specifically associated with the treatment of very advanced parasitic disease. Over 300 million people continue to take ivermectin every year for ongoing treatment of river blindness and other parasitic diseases.

While ivermectin was first approved for the treatment of parasites in animals such as livestock and household pets in 1981, it is misleading to portray it as primarily a veterinary drug: in fact the process of adapting it for use in humans began simultaneously with its introduction for veterinary applications, in 1978, reflecting the drug’s obvious potential and the extreme urgency of humanitarian demands for an effective anti-parasitic drug. Soon after its approval for human use in 1987 ivermectin was adopted as the sole control measure for river blindness in Africa, supplanting campaigns relying on the mass spraying of insecticides over very large regions.  

Like most drugs ivermectin can have side effects, which are however usually temporary and limited in the majority of patients. Ivermectin may be contra-indicated in individuals with liver or kidney disease, cancer, HIV/AIDS, or other conditions that can weaken the immune system. Ivermectin’s safety has not been established for children weighing less than 15 kg (33 pounds) and pregnant women. Like any prescription medication it is extremely ill-advised for individuals to attempt to self-medicate with ivermectin, as taking drugs while not under a doctor’s supervision can result in serious injury or death through overdoses or interactions with other drugs, among other risks. Nobody should ever take the veterinary form of ivermectin or any other drug due to the clear danger of toxicity resulting from overdosing as well as the potential presence of other drugs and chemicals in preparations intended for veterinary use.  To find a doctor who can prescribe ivermectin for COVID-19 if appropriate, click here.