Chemical formula: C₁₈H₂₆ClN₃ Molecular mass: 319.872 g/mol PubChem compound: 2719
Chloroquine interacts in the following cases:
Chloroquine should be used with caution in patients receiving drugs known to prolong the QT interval e.g. Class IA and III antiarrhythmics, tricyclic antidepressants, antipsychotics, some anti-infectives due to increased risk of ventricular arrhythmia.
In vitro work has shown that the concomitant use of drugs such as multidrug and toxin extrusion protein (MATE1) inhibitors (e.g. ciprofloxacin, cimetidine, omeprazole, pyrimethamine) may impact the renal clearance of chloroquine, which could theoretically lead to increased levels of chloroquine and potentially overdosage. In addition, care should be taken when alkalinization of urine occurs as this may reduce chloroquine renal excretion.
Caution is necessary when giving chloroquine to patients with renal disease or hepatic disease.
Antacids (aluminium, calcium and magnesium salts) and adsorbents (e.g. kaolin) may reduce the absorption of chloroquine, so should be taken well separated from chloroquine (at least four hours apart).
Pre-exposure intradermal human diploid-cell rabies vaccine should not be administered to patients taking chloroquine as this may suppress the antibody response. When vaccinated against rabies, that vaccine should precede the start of the antimalarial dosing, otherwise the effectiveness of the vaccine might be reduced.
Chloroquine may lower the convulsive threshold and thus antagonise the actions of antiepileptics.
There is a theoretical risk of inhibition of intra-cellular α-galactosidase activity when chloroquine is co-administered with agalsidase.
If the patient is taking ciclosporin then chloroquine may cause an increase in ciclosporin levels.
Cimetidine inhibits metabolism of chloroquine (increased plasma concentration).
Hydroxychloroquine and possibly chloroquine increase plasma concentration of digoxin.
Halofantrine should not be administered with chloroquine.
Increased Thyroid Stimulating Hormone levels have been observed with the concomitant use of ofchloroquine with levothyroxine, dosage adjustment of thyroid medication may be necessary.
There is increased risk of convulsion in co-administration of chloroquine with mefloquine.
Chloroquine significantly reduces levels of praziquantel. Caution is therefore advised during co-administration. Prescribers may consider increasing the dose of praziquantel if the patient does not respond to the initial dose.
Chloroquine has been shown to prolong the QTc interval in some patients.
Chloroquine should be used with caution in patients with congenital or documented acquired QT prolongation and/or known risk factors for prolongation of the QT interval such as:
as this may lead to an increased risk for ventricular arrhythmias, sometimes with fatal outcome.
The magnitude of QT prolongation may increase with increasing concentrations of the drug. Therefore, the recommended dose should not be exceeded.
If signs of cardiac arrhythmia occur during treatment with chloroquine, treatment should be stopped and an ECG should be performed.
Caution is advised in patients with glucose-6-phosphate dehydrogenase deficiency, as there may be a risk of haemolysis.
Chloroquine should be used with care in patients with a history of epilepsy. Potential risks and benefits should be carefully evaluated before use in subjects on anticonvulsant therapy or with a history of epilepsy as rare cases of convulsions have been reported in association with chloroquine.
A small number of cases of diffuse parenchymal lung disease have been identified in patients taking chloroquine. A response after therapy with steroids has been observed in some of these cases.
Chloroquine has been shown to cause severe hypoglycaemia including loss of consciousness that could be life threatening in patients treated with and without antidiabetic medications. Patients treated with chloroquine should be warned about the risk of hypoglycaemia and the associated clinical signs and symptoms. Patients presenting with clinical symptoms suggestive of hypoglycaemia during treatment with chloroquine should have their blood glucose level checked and treatment reviewed as necessary.
The use of chloroquine in patients with psoriasis may precipitate a severe attack.
Irreversible retinal damage and corneal changes may develop during long term therapy and after the drug has been discontinued. Ophthalmic examination prior to and at 3–6 monthly intervals during use is required if patients are receiving chloroquine:
Caution is also necessary in patients with porphyria. Chloroquine may precipitate severe constitutional symptoms and an increase in the amount of porphyrins excreted in the urine. This reaction is especially apparent in patients with high alcohol intake.
Cases of drug rash with eosinophilia and systemic symptoms (DRESS) syndrome have been identified in patients taking chloroquine alone or in combination with proguanil. Recovery after discontinuation of treatment and response after therapy with steroids has been observed.
Acute extrapyramidal disorders have been reported during treatment with chloroquine, usually disappearing on discontinuation of treatment and/or on symptomatic treatment.
Considerable caution is needed in the use of chloroquine for long-term high dosage therapy and such use should only be considered when no other drug is available. Patients on long-term therapy should also be monitored for cardiomyopathy.
In patients receiving chloroquine therapy cases of cardiomyopathy have been reported, leading to heart failure, sometimes with fatal outcome. If signs and symptoms of cardiomyopathy occur during treatment with chloroquine, treatment should be stopped.
Chloroquine and hydroxychloroquine have potential to increase symptoms of myasthenia gravis and thus diminish effect of neostigmine and pyridostigmine.
Chloroquine should not be used during pregnancy unless, in the judgement of the physician, potential benefit outweighs the risk.
Malaria in pregnant women increases the risk of maternal death, miscarriage, still-birth and low birth weight with the associated risk of neonatal death. Travel to malarious areas should be avoided during pregnancy but, if this is not possible, women should receive effective prophylaxis.
There is evidence to suggest that chloroquine given to women in high doses throughout pregnancy can give rise to foetal abnormalities including visual loss, ototoxicity and cochlear-vestibular dysfunction.
Although chloroquine is excreted in breast milk, the amount is too small to be harmful when used for malaria prophylaxis but as a consequence is insufficient to confer any benefit on the infant. Separate chemoprophylaxis for the infant is required. However, when long-term high doses are used for rheumatoid disease, breast feeding is not recommended.
Defects in visual accommodation may occur on first taking chloroquine and patients should be warned regarding driving or operating machinery.
The adverse reactions which may occur at doses used in the prophylaxis or treatment of malaria are generally not of a serious nature. Where prolonged high dosage is required, i.e. in the treatment of rheumatoid arthritis, adverse reactions can be of a more serious nature.
Undesirable effects are listed by MedDRA System Organ Classes.
Assessment of undesirable effects is based on the following frequency groupings:
Very common: ≥1/10
Common: ≥1/100 to <1/10
Uncommon: ≥1/1,000 to <1/100
Rare: ≥1/10,000 to <1/1,000
Very rare: <1/10,000
Not known: cannot be estimated from the available data
Not known: Bone marrow failure, Aplastic anaemia, Agranulocytosis, Thrombocytopenia, Neutropenia, Pancytopenia
Not known: Hypersensitivity and anaphylactic reactions, including urticaria, angioedema and vasculitis
Not known: Hypoglycaemia
Rare: Hallucinations
Not known: Psychotic disorder including anxiety, personality change, Insomnia, Confusion, Depression
Not known: Convulsion, Visual field defects, Headache, Neuromyopathy, Acute extrapyramidal disorders (such as dystonia, dyskinesia, tongue protrusion, torticollis)
Not known: Retinal degeneration, Macular defects of colour vision, Pigmentation, Optic atrophy scotomas, Blindness, Corneal opacity and pigmented deposits, Vision blurred, Accommodation disorder, Diplopia
Not known: Tinnitus, Hypoacusis, Deafness neurosensory
Rare: Cardiomyopathy
Not known: Atrioventricular block, QT-prolongation
Not known: Hypotension
Not known: Diffuse parenchymal lung disease
Not known: Gastrointestinal disorder, Nausea, Vomiting, Diarrhoea, Abdominal pain
Rare: Changes in liver function, including hepatitis and abnormal liver function tests
Not known: Macular, urticarial and purpuric skin eruptions, Alopecia, Erythema multiforme, Drug reaction with eosinophilia and systemic symptoms syndrome (DRESS), Stevens-Johnson syndrome (SJS), Toxic epidermal necrolysis (TEN), Precipitation of psoriasis, Pruritus, Photosensitivity reaction, Lichenoid keratosis, Pigmentation disorder*, Exfoliative dermatitis, Acute generlised exanthematous pustulosis (AGEP)
Not known: Myopathy
Not known: Electrocardiogram change**
* Long term use
** At high doses
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