NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

Amiodarone and dronedarone: monitoring

Amiodarone is an effective anti-arrhythmic, but it is associated with significant adverse effects: thyroid toxicity, hepatotoxicity and pulmonary toxicity. SIGN have provided clear guidance on amiodarone use and monitoring to minimise drug related risks.

 

The NHSGGC Formulary restricts amiodarone to specialist initiation. The prescriber who initiates the drug should ensure that baseline assessments are undertaken and the drug is titrated to the minimum effective dose. Baseline monitoring consists of pulmonary function (including transfer factor of carbon monoxide), thyroid (TFTs) and liver function tests (LFTs).

 

Once the patient has been stabilised on the minimum effective dose, the on-going monitoring is the responsibility of the general practitioner. This follow up routine monitoring consists of TFTs and LFTs every six months

 

Patients receiving amiodarone therapy should be provided with information on potential adverse effects.  Patients with new or increasing cough or breathlessness during amiodarone therapy should be promptly referred for respiratory evaluation. 

 

A recent retrospective audit in four NHSGGC general practices identified 46 patients prescribed amiodarone.  Six monthly LFT and TFT monitoring occurred in 33% and 24% of patients with 21% of patient respectively receiving both tests.  It is estimated that approximately 800 people in NHSGGC receive amiodarone with no more than 5 patients per GP practice.

 

Dronedarone, a less commonly prescribed antiarrhythmic also requires LFT monitoring before initiation, during titration and throughout treatment. Currently there are approximately 60 people receiving dronedarone in NHSGGC. The Formulary notes that dronedarone should only be initiated and monitored under specialist supervision. In cases where GPs continue the prescribing, associated monitoring should continue to be the responsibility of the acute sector.

 

NHSGGC ScriptSwitch® messages in primary care are being updated to support monitoring of TFTs and LFTs to minimise amiodarone and dronedarone drug related risks.