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Lipitor, interactions and the risk of haemorrhagic stroke in patients with recent stroke

Pfizer has informed Healthcare Professional of updated prescribing advice for Atorvastatin ( Lipitor ). The new advice relates to interactions and the risk of haemorrhagic stroke in patients with recent stroke.

Interactions with other medicines

Atorvastatin levels may increase when administered with drugs that inhibit its metabolism ( via cytochrome P450 CYP3A4 inhibition ). Its use with these interacting drugs may increase the risk of side-effects and, if possible, alternative ( non-interacting ) therapies should be considered instead of these medications. If the use of Atorvastatin and an interacting drug is considered essential, then:

• Always start Atorvastatin at the lowest dose ( ie, 10 mg ) and monitor lipids carefully before titrating the dose;

• Consider temporary cessation of Atorvastatin if the use of an interacting drug is for a short period only ( eg, short-term use of antibiotics such as Clarithromycin ) • Note new advice for the maximum dose of Atorvastatin when used with specific drugs: with Cyclosporin: do not exceed 10 mg Atorvastatin; with Clarithromycin do not exceed 20 mg Atorvastatin; with Itraconazole do not exceed 40 mg Atorvastatin.

Prescribers are reminded to consider other possible interactions for Atorvastatin, which are given in the Summary of Product Characteristics ( SPC ). These include: HIV protease inhibitors; Warfarin; fibrates; Ezetimibe; Verapamil; Diltiazem; Amiodarone; grapefruit juice; and CYP3A4 inducers ( such as St John’s Wort ).

Risk of haemorrhagic stroke

Evidence from a post hoc analysis of the SPARCL study suggests that patients with recent haemorrhagic or lacunar stroke ( without coronary heart disease ) may have an increased risk of haemorrhagic stroke when treated with 80 mg Atorvastatin daily.
In the Stroke Prevention by Aggressive Reduction in Cholesterol Levels ( SPARCL ) study, the effect of Atorvastatin 80 mg daily or placebo on stroke was evaluated in 4731 patients who had a stroke or transient ischemic attack ( TIA ) within the preceding 6 months and no history of coronary heart disease ( CHD ).

In a post-hoc analysis of stroke subtypes, Atorvastatin 80 mg reduced the incidence of ischemic stroke ( 9.2% vs 11.6%, p=0.01 ) and increased the incidence of haemorrhagic stroke ( 2.3% vs 1.4%, p=0.02 ) compared to placebo.

The increased risk of haemorrhagic stroke was particularly noted in patients with prior haemorrhagic stroke or lacunar infarct at study entry. For patients with prior haemorrhagic stroke or lacunar infarct, the balance of risks and benefits of Atorvastatin 80 mg is uncertain and the potential risk of haemorrhagic stroke should be considered carefully before initiating treatment.

Source: Medicines and Healthcare product Regulatory Agency – MHRA, 2008