News in brief: Maternity referral guidelines & Simvastatin

New maternity referral guidelines released

In July 2011, the Ministry of Health updated its Referral Guidelines for Lead Maternity Carers (LMC). This updates and replaces the referral process as outlined in “The role of General Practice in the care of pregnant women”, BPJ 35 (Apr, 2011 ).

The revised Referral Guidelines are intended to:

• Improve maternity care safety and quality
• Improve the consistency of consultation, transfer and transport processes
• Give confidence to women, their families/whānau, and other practitioners if a primary care or specialist consultation or a transfer of clinical responsibility is required
• Promote and support coordination of care across providers

The previous Guidelines recommended a three tier referral system for LMCs. The revised Guidelines recommend four categories of referral (Table 1).

The referral process to Primary Care involves the following steps:

1. The LMC determines that a referral to the woman’s General Practitioner is warranted and discusses this with the woman and gains her consent.
2. The LMC makes a referral to the woman’s General Practitioner (or other Primary Care practitioner), but remains responsible for the woman’s maternity care.
3. The General Practitioner assesses the woman and responds to the referring LMC in writing, recommending a plan of care for the woman or her baby.
4. If the condition requires input from another practitioner, the General Practitioner will discuss this with the woman and the LMC and make a referral to the practitioner and inform the LMC.

Conditions for which referral to a General Practitioner or other Primary Care practitioner is recommended include: cardiac arrhythmia/palpitations which are recurrent, persistent or associated with other symptoms; hypothyroidism; symptomatic cholelithiasis (gall stones); inactive inflammatory bowel disease; contact with tuberculosis; controlled epilepsy; current alcohol or drug misuse/dependency; depression and anxiety disorders; mild or moderate asthma; acute respiratory conditions; influenza-like illness; postnatal depression; minor abnormalities in the newborn; undescended testes in newborn boys; mother on a medicine which poses a risk to the foetus e.g. carbimazole, antipsychotics, antidepressants, anticonvulsants.

The Guidelines have been designed to enhance communication, collaboration and documentation between clinical providers. LMCs are encouraged to provide relevant information to the woman’s General Practitioner throughout the course of her pregnancy, and likewise, the General Practitioner should share all relevant information with the LMC (e.g. if the General Practitioner requests the first antenatal screening tests). The Guidelines ensure that the woman, her infant and family/whanau are at the centre of all decision making.

Table 1: Referral guidelines for LMCs (MoH, 2011)

Simvastatin: risk associated with high doses

The United States Food and Drug Administration (FDA) has issued a recommendation that the use of high-dose simvastatin (80 mg) is restricted, due to increased risk of myopathy. The recommendation states that simvastatin 80 mg should only be prescribed if a patient has previously been taking the medicine for longer than 12 months with no signs of myopathy. Furthermore, prescriptions for 80 mg simvastatin should not be issued to new patients and those already taking simvastatin should not have their dose increased to 80 mg per day.¹

The FDA advice comes following the analysis of the SEARCH trial, which found that patients taking 80 mg per day of simvastatin had an increased risk of myopathy compared to patients taking lower doses of the same medicine, or other medicines of the same class.^1,2 The study, which included over 12 000 people, found that 52 patients in the 80 mg group, and one in the 20 mg group, developed myopathy. Approximately 60% of reported cases of myopathy were due to a genetic variation affecting the uptake of simvastatin into the liver, resulting in increased plasma levels of simvastatin which in turn increases the risk of myopathy.¹ Most cases were likely to occur in the first year of treatment. Increased age and female gender were also found to increase the risk of myopathy.¹

Symptoms of myopathy, which in severe cases can develop into rhabdomyolysis, include; muscle pain and tenderness, weakness and dark or red urine. Confirmation of diagnosis can be achieved by testing for elevated serum creatine kinase levels.³

Medsafe response

Medsafe is currently in the process of updating the data sheets for all medicines available in New Zealand that contain simvastatin.

For example, the changes to the Lipex data sheet include:

• In the Dosing and Administration section: The 80 mg dose of LIPEX should be used only for those patients who have not achieved their LDL-C goal utilising the 40 mg dose.
• The following Contraindications have been added:
  • Myopathy secondary to other lipid lowering agents
  • Concomitant administration of potent CYP3A4 inhibitors, e.g. itraconazole, ketoconazole, posaconazole, HIV protease inhibitors, erythromycin, clarithromycin, telithromycin and nefazodone)
  • Concomitant administration of gemfibrozil, cyclosporin or danazol
• The inclusion of additional information in the Warnings and Precautions section, including: The risk of myopathy is greater in patients on simvastatin 80 mg compared with other statin-based therapies with similar LDL-C lowering efficacy. Therefore the 80 mg dose of LIPEX should only be used in patients at high risk for cardiovascular complications who have not achieve their treatment goals on lower doses and when the benefits are expected to outweigh the potential risks. In patients taking LIPEX 80 mg for whom an interacting agent is needed, a lower dose of LIPEX or an alternative statin regimen with less potential for drug-drug interactions should be used.
• The addition of information (including dose caps) in the drug interactions section of the Warnings and Precautions section
• Additional information in the Interactions section

A Prescriber Update will also be released shortly advising of restrictions to the 80 mg dose of simvastatin in New Zealand.

Use of high dose simvastatin

In New Zealand, simvastatin, combined with diet and exercise, remains the first-line cholesterol lowering treatment for patients with an estimated five year CVD risk of 15–20%. The usual dose is simvastatin 20–40 mg per day, which may be increased to 80 mg in patients who require intensive treatment. It is important to remember that the statin dose response is not linear, i.e. the 80 mg dose reduces LDL cholesterol by an additional 6% over the 40 mg dose.

In patients taking 80 mg simvastatin, consider switching to atorvastatin 40 mg daily, which is an equivalent dose. In addition, consider that the benefits of statin treatment for elderly people are less clear than in younger populations,⁴ therefore older patients may benefit more from a reduction in dose.

For further information about prescribing statins see: “An update on statins”, BPJ 30 (Aug, 2010).

To view previous Medsafe guidance on statin-induced myopathy see: “Statin interactions: reports of serious myopathy” Prescriber Update 2011;32(2), available from: www.medsafe.govt.nz.