引 致 更 改 給 病 人 的 產 品 資 訊 的 藥 物 不 良 反 應 警 示
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| The United Kingdom: Statins: very infrequent reports of myasthenia gravis (English only) |
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Medicines and Healthcare products Regulatory Agency (MHRA) announces that there has been a very small number of reports of new onset or aggravation of pre-existing myasthenia gravis with atorvastatin, pravastatin, lovastatin, fluvastatin, simvastatin, rosuvastatin and pitavastatin (single-ingredient and fixed-dose combination products) globally.
A recent European review recommended new warnings on the risk of new onset or aggravation of pre-existing myasthenia gravis with multiple statins. The findings of this review were considered by the Pharmacovigilance Expert Advisory Committee (PEAG) of the Commission on Human Medicines, which agreed with the recommendations. The product information of all statins is being updated to list myasthenia gravis and ocular myasthenia gravis as adverse drug reactions with a frequency ‘not known’. New warnings will also be added to the Summaries of Product Characteristics and Patient Information Leaflets. In reviewing this issue, the PEAG recommended that the MHRA inform healthcare professionals and patients of the newly identified risk. They also noted that existing International Consensus Guidance for Management of Myasthenia Gravis (2020) states that statins may rarely worsen or precipitate myasthenia gravis.
Myasthenia gravis is a rare long-term auto-immune neuromuscular disorder characterised by fluctuating weakness of the voluntary muscles that control eye movements, facial expression, speaking, swallowing, limb movement and breathing. Symptoms include drooping eyelids, double vision, problems with chewing or swallowing, speech disturbance, limb weakness and shortness of breath. Myasthenia gravis can affect people of any age, generally starting in women under 40 years old and men over 60 years old. Drug treatment can usually help keep the symptoms under control. Several triggers have been identified for patients with myasthenia gravis that can aggravate symptoms. These include stress, tiredness, infections, excess physical activity, surgery, changes in immunomodulatory treatments and medicines. Some examples of medicines that have been associated with worsening symptoms include several groups of antibiotics and beta-blockers. Reports of worsening myasthenia gravis with medicines are very rare.
From 14 Jun 1995 up to 19 Jun 2023, the MHRA has received 10 United Kingdom Yellow Card reports citing a statin as a suspect medicine for an adverse drug reaction involving myasthenia gravis; with reports received for simvastatin, atorvastatin and pravastatin. This is against a background of extensive use of statins. In 2022 alone, more than 9.5 million patients were dispensed a statin in the United Kingdom. Across the 10 Yellow Card reports the median age of the patients was 66 years (affected patient age groups ranged from 40 to 89 years with the majority of reports concerning those aged over 60 years). Symptoms reported include double vision, difficulty with speech and swallowing, weakness in limbs and shortness of breath. Onset of symptoms started from a few days up to three months after starting statin therapy. Three of the 10 cases involved the recurrence or exacerbation of symptoms in patients with known myasthenia gravis. There was also one report of positive rechallenge with symptoms recurring on reinitiating statin therapy. While four of the reports indicated that patients were hospitalised, the majority of patients had recovered or were recovering at the time of reporting. No fatal United Kingdom reports have been received.
At this time there is insufficient data to conclude whether different statins, different duration of therapy and different dosing levels alter the risk of experiencing myasthenia gravis. It is also unknown whether the development of new onset myasthenia gravis following statin therapy is a transient or permanent condition.
Advice for healthcare professionals:
- There have been some suspected reports of new onset or aggravation of pre-existing myasthenia gravis or ocular myasthenia gravis associated with statin use; the current frequency of these adverse events is not known but given the extensive use of statins in the population, the reports are understood to be very infrequent.
- The majority of United Kingdom reports note that the patient recovered after stopping statin treatment, while a minority continued to experience symptoms; recurrence of symptoms has been reported when patients restarted on the same or a different statin.
- Refer patients presenting with suspected new onset myasthenia gravis after starting statin therapy to a neurology specialist; it could be necessary to discontinue statin treatment depending on the assessment of the individual benefits and risks.
- Advise patients with pre-existing myasthenia gravis to be alert to aggravation of symptoms while taking a statin; it could be necessary to discontinue statin treatment depending on the assessment of the individual benefits and risks.
Please refer to the following website in MHRA for details:
http://www.gov.uk/drug-safety-update/statins-very-infrequent-reports-of-myasthenia-gravis
In Hong Kong, there are registered pharmaceutical products containing atorvastatin (104 products), lovastatin (3 products), pravastatin (8 products), rosuvastatin (67 products) and simvastatin (86 products). All products are prescription-only medicines. There is no registered pharmaceutical product containing fluvastatin or pitavastatin.
So far, the Department of Health (DH) has received adverse drug reaction related to atorvastatin (21 cases), rosuvastatin (20 cases) and simvastatin (8 cases), but these cases were not related to myasthenia gravis. The DH has not received any case of adverse drug reaction related to lovastatin and pravastatin.
In light of the above MHRA’s announcement, letters to inform local healthcare professionals will be issued, and the matter will be discussed by the Registration Committee of the Pharmacy and Poisons Board.
Ends/Wednesday, Sep 27, 2023
Issued at HKT 16:00
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