Month: March 2024

The New Zealand General Practice Podcast

opotikigp family medicine, general practice, Healthcare , ,

Clinical Snippets March 2024

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Dr Dave Maplesden educates Dr Jo about….

CLINICAL SNIPPETS – MARCH 2024 

1.  Prescribing 

Health Pathways has released a new section on practical prescribing aimed mainly at new prescribers but some helpful reminders for veteran prescribers.  Covers most general aspects of prescribing including legal requirements.  Some practical information includes: 

  • If you prescribe intermittent PRN medicines e.g., two tablets QID PRN, without ordering a specific amount then the pharmacy will dispense the maximum allowable amount i.e., 720 tablets for three months. If you continue to print this medicine automatically on your repeat prescriptions the patient is liable to receive excessive amounts. This has safety implications, especially if it is a medicine of potential abuse such as codeine-containing medicines. 
  • When a patient tells a prescriber they have different numbers of each of their medications, write “Please vary quantities for patient stock management.” Pharmacists can then dispense the required quantities to bring medications into line. 
  • Patients not eligible for pharmaceutical subsidies but covered by ACC  for an injury may be eligible to claim back the cost of usually subsidised prescriptions related to that injury using an ACC249 form (which the pathway suggest the prescriber gives to the patient) 
  • Pharmacists check that a medicine or a dose of medicine is correct by comparing the new prescription with the patient’s medicine history.  To avoid the pharmacist needing to check with you that a change in the prescription is deliberate, please underline and annotate any change from the previous prescription. Annotation of changes is important. Pharmacists’ systems are not linked and if a patient does not return to the same pharmacy, the pharmacist may be unaware of a change in prescription for that patient. 

2.  Concussion   

  • BPACs Best Practice Bulletin: Issue 92 includes updated Sport Concussion Guidelines from ACC including a six-stage graduated return to education/work & sport protocol.  It is worth familiarising yourself with the protocol to ensure patients are given a consistent message regarding return to sport.  The protocol notes day 14 is the earliest time at which return to normal work/study and sports specific training should be considered, and day 21 is the earliest at which return to competitive sport should be considered.  
  • There is reference to the recent ACC statement on post-concussion syndrome:  ACC considers that post-concussion syndrome is an unhelpful and out-dated clinical construct. Our view is that there are risks inherent in continuing to diagnose clients with this condition, not least that disabling symptoms will be misattributed to this condition rather than to potentially reversible medical, psychological, or psychiatric factors that remain undiagnosed and untreated. Consequently, ACC no longer accepts ‘post-concussion syndrome’ as a covered injury. Where clients/patients have persisting symptoms that clinicians consider are caused by concussion, the appropriate covered injury would be ‘concussion’. Symptoms that persist beyond three months are most appropriately described as ‘persisting concussion symptoms.’ 
  • I’ll put in my regular plug for use of the Brain Injury Screening Tool (BIST-2) (not just for sports related concussion) which is validated for patients aged over 8 years and is designed to be completed in about six minutes.  It gives objective baseline and progress measures covering physical, vestibular-ocular and cognitive symptoms of concussion.   
  • There is an excellent 2022 BPAC article on diagnosing and managing concussion in primary care.    

3.  Two defibrillators? 

  • The February edition of NZ Doctor describes a new emergency procedure for cardiac arrest known as double sequential external defibrillation (DSED) which has been adopted here, the second country after Canada to do so.  The article notes that early defibrillation can dramatically improve the likelihood of surviving a cardiac arrest but around 20% of patients whose cardiac arrest is caused by VF or pulseless VT don’t respond to the standard defibrillation approach.  The use of DSED has been shown to double the survival rate of such patients.  
  • DSED provides rapid sequential shocks to the heart using two defibrillators. The pads are attached in two different locations: one on the front and side of the chest, the other on the front and back. A single operator activates the defibrillators in sequence, with one hand moving from the first to the second. New Zealand ambulance data from 2020 to 2023 identified about 1,390 people who could potentially benefit from novel defibrillation methods. This group has a current survival rate of only 14%.   
  • Relevant paramedic guidelines are to be updated reflecting the new approach including that if ventricular fibrillation or pulseless ventricular tachycardia persist after two shocks with standard defibrillation, the DSED method should be administered. Two defibrillators need to be available, and staff must be trained in the new approach.   

4.  Equitable prescribing 

  • Issue 230 of GP Research Review reviews a recently published study on inequities in pre-pregnancy folic acid use in Central and South Auckland. The study notes that rates of neural tube defects are markedly higher among Māori (4.58/10,000 live births), and Pacific peoples (4.09/10,000 live births) as compared with non-Māori, non-Pacific peoples (2.81/10,000 live births).  
  • Only 46% of the 400 women surveyed as part of the study reported using pre-pregnancy folic acid supplementation. Rates were lower among women who did not intend to become pregnant (21%) or were “pregnancy-ambivalent” (27%) than in those who intended their pregnancy (58%). Women who identified as European, Middle Eastern, Latin American or African were around five times more likely to use supplementation than Māori.  Supplementation was also more likely among those managed by a private obstetrician versus a midwife and in women aged over 30 years. 
  • The study concluded Low rates of pre-pregnancy folic acid supplementation exist in Auckland with significant ethnic disparity. Mandatory fortification of non-organic wheat is important, but supplementation is still recommended to maximally reduce risk. 

5.  Medication supply issues and brand changes 

  • Morphine oral liquid (RA-Morph) 1 mg per ml and 10 mg per ml strengths are out of stock, and remaining supply of RA-Morph 2 mg per ml and 5 mg per ml will expire at the end of March.  Re-supply RA-Morph 1 mg per ml is expected by June-2024. Other strengths of RA-Morph are expected later in 2024.  This leaves two unapproved but funded (s29) brands of 2mg per ml strength available – Wockhart and Oramorph.  Further detail and prescribing advice is available on He Ako Hiringa website.   
  • Omeprazole 20 and 40mg capsules – monthly dispensing from 1 March 2024 until stocks arrive (expected April 2024) 
  • Oestradiol valerate 1mg tabs (Progynova) – monthly dispensing from 1 March 2024 until stocks arrive (expected June 2024).  2mg tabs not affected. 
  • Mesalazine 800mg tabs (Asacol) – shortage expected until July 2024.  Two x 400mg tabs suitable alternative 
  • Olsalazine 250 and 500mg tabs (Dipentum) – both unavailable with 500mg expected available from April 2024.  Consider change to alternative medication eg mesalazine 
  • The funded bisoprolol brand is changing from 1 April 2024 when bisoprolol-Mylan and Viatris will no longer be funded.   A patient information leaflet about the brand change is available on the Pharmac website.  
  • From 1 March 2024, Pharmac has removed the requirement for annual renewal of SA numbers for patients taking sacubitril with valsartan (Entresto), for heart failure.  
  • Modafinil – contra-indications (contraindicated in pregnancy), contraception and conception, pre-treatment screening, and patient advice has been updated in NZF.  This includes pretreatment screening with BP, ECG and excluding pregnancy, and Effective contraception is recommended during treatment and for 2 months after stopping treatment. Effectiveness of hormonal contraception (including contraceptive pills, implants, injectables and hormone releasing intrauterine devices) may be reduced.  The UK FSRH gives current guidance on contraceptive options in patients taking enzyme inducers.    

6.  Frank’s sign 

Issue 111 of Cardiology Research Review reports a Spanish study looking at Frank’s sign (Sanders T Frank – 1973) and cardiovascular risk.  Frank’s sign is a diagonal earlobe crease.   The estimated cardiovascular mortality risk was significantly higher in individuals who presented diagonal earlobe crease. The number of individuals with moderate, high, or very high cardiovascular risk increased significantly as the presence of the crease increased (23.8% had no crease, 35.6% had unilateral creases, and 58% had bilateral creases). The mean cardiovascular risk estimated was significantly higher for individuals with longest and deepest diagonal earlobe crease, and with accessory creases.  The conclusion:  The diagonal earlobe crease is independently associated with higher cardiovascular risk scores, especially when the crease is complete, bilateral, deep, and has accessory creases.  

7.  The limping adolescent 

  • Beware the child with unexplained limp or knee pain.  I’ve recently reviewed a case of missed diagnosis of SUFE in a slim 11yo female which had disastrous consequences for her – stable mild slip converting to a severe acute slip. 
  • Health Pathways has a section devoted to SUFE partly because of the potentially severe consequences of missed or late diagnosis.  This includes the practice point:  All children complaining of knee pain need exclusion of hip pathology. If there is no evidence of knee pathology on examination, arrange hip X-ray with AP pelvis and frog lateral view.  However, if you suspect an acute SUFE on the basis of history and examination, refer immediately for orthopaedic assessment rather than imaging.   
  • As a quick refresher, SUFE usually occurs in the 8-15 year age group, more common in males and a more than half of sufferers are overweight or obese.   The most common presentation is a chronic slip with gradual movement of the epiphysis and the patient may present with vague chronic or intermittent aching pain in hip, groin, thigh or medial knee. 15% of patients only have thigh or knee pain. Pain worsens with physical activity and there is usually no preceding trauma. It may be bilateral (18-50%).  An acute slip presents after a sudden event with inability to weight bear and appearance of a hip fracture.  You can get an acute slip on background of a chronic slip (sudden exacerbation of symptoms in a setting of more consistent low-grade symptoms, may be episodic). 
  • A chronic slip may present with persistent or episodic limp. Foot on the affected side may be out-turned. Loss of internal rotation at hip.  Leg length shortening may be present.  When the hip is flexed passively to 90º, the thigh will abduct and roll into external rotation. Examine the knee to rule out local process at the knee to account for knee pain.  With an acute slip there is a marked limp and Trendelenburg gait and often an inability to weight bear.  There may be an external rotational deformity of the hip and shortening of the affected leg. 
  • The annual incidence of SUFE in the 0–16-year age group is around 5/100,000 meaning around 40-50 cases in NZ annually so you may never see one.  An Australian study suggests there is delayed diagnosis (weeks to years) in around 60% of cases of chronic stable slip, and most patients (76%) present initially to their GP.      

The New Zealand General Practice Podcast

opotikigp family medicine, general practice, Healthcare , , , , , , ,
Clinical Snippets February 2024

Shownotes

Clinical Snippets February 2024

1.  ACE and ARB and statin use in pregnancy – DON’T

The NZF notes that ACE inhibitors should be avoided at all stages of pregnancy. Fetal skull defects have been reported following first trimester exposure to ACE inhibitors although evidence of teratogenicity is inconclusive. In the second and third trimesters ACE inhibitors can cause abnormalities including fetal growth retardation, oligohydramnios and fetal or neonatal renal failure. Fetal death in utero has also been reported. Pregnant women who are taking an ACE inhibitor should be changed to an alternative antihypertensive as soon as possible.  Like ACE inhibitors ARBs should be avoided in pregnancy, particularly in the second and third trimesters, as similar effects to those caused by ACE inhibitors in pregnancy are expected.  

NZF notes also that Statins should be avoided in pregnancy as congenital anomalies have been reported and the decreased synthesis of cholesterol possibly affects fetal development. The individualstatin monographs state the drug is contraindicated during the first trimester and adequate contraception is required during treatment and for 1 month afterwards.  However, a 2022 metanalysis and systematic review noted there are some patients for whom there may be a significant benefit of maintaining statin therapy, in particular in the second and third trimesters. The risk and benefit of statins treatment during pregnancy need to be evaluated in an individualized approach and every trimester apart.

2.  Monitoring lithium drug interactions

A September NZ Doctor article on monitoring drug interactions with lithium is a helpful refresher on monitoring recommendations for patients on lithium therapy:

(i)  Usual monitoring: (current reference range for chronic use is 0.6-0.8 mmoL/L):

  • Three to six-monthly (depending on stability) – serum lithium level, electrolytes, eGFR.
  • Six-monthly – thyroid function, calcium, weight.
  • Annually (if over age 40 or obese) – HbA1c, lipids, consider ECG.

(ii)  When adding or removing medicines:

  • ACE inhibitors – baseline serum lithium level and renal function tests, then weekly for six weeks or until stable. For “at-risk” people (impaired renal function, volume depletion or heart failure) consider further two-weekly checks for six weeks.

20 to 35 % of people will have an increase in lithium levels if an ACE inhibitor is added to their regime, usually by around 33 %. The interaction can be delayed for up to five weeks, so it is important not to be reassured by steady lithium levels initially.  ARB interaction less likely but dose dependent (ARB) increases in lithium levels of up to 20 % after up to five weeks of treatment have been reported. 

  • Diuretics – baseline serum lithium level and renal function tests, then weekly for four weeks.

If a thiazide needs to be introduced, there may be a rapid increase in serum lithium levels by 20-25 % in 3-10 days, although this effect may also be delayed.  Loop diuretics have less impact, with potentially only up to a 20% increase in levels, and potassium-sparing diuretics appear to have no effect.

  • NSAIDs – baseline serum lithium level and renal function tests, then weekly for two weeks or until stable.

This interaction is well described for decreasing lithium clearance and increasing its toxicity, although it is unpredictable. While the average decrease in lithium clearance is usually 10-25%, there is wide variation, especially in people with impaired renal function. It is unlikely that COX-2 inhibitors would be any different to traditional NSAIDs regarding this interaction.

The risk is cumulative with concomitant use of ACE inhibitors, diuretics and NSAIDs.

3.  Shared care clozapine

The October 2023 NZ Doctor includes a refresher on shared care prescribing of clozapine.  Points include:

(i)  Clozapine can only be initiated by a psychiatrist. In some localities within Te Whatu Ora, GPs and nurse practitioners can be responsible for ongoing prescribing under the supervision of a psychiatrist. GPs can also prescribe for those with stable illness in collaboration with a community mental health team.  Patients are considered stable if they have been taking clozapine continuously for two years, had no mental-health-related hospital admissions in the last 12 months, are not taking other medications requiring close monitoring by a psychiatrist, and have been adherent to treatment and attending appointments.

(ii)  Due to the risk of agranulocytosis, all patients prescribed Clopine in New Zealand must be registered to ClopineCentral™ (the Clopine Monitoring System) or CareLink Plus (the Clozaril Monitoring System) by a registered medical practitioner.  Prescribing physicians must also register themselves onto the relevant monitoring system to access patient information. Brand swapping between clozapine products is discouraged and should occur on the advice of the initiating clinician or team. 

(iii)  The adverse effect and drug interaction profile of clozapine is wide (in particular agranulocytosis, severe constipation and cardiomyopathy/myocarditis) and there are specific requirements for pre-prescribing screening and subsequent monitoring which are critical to reduce the risk of patient harm.  There is comprehensive practical information available on HealthPathways (not yet localised for Midlands) and in publications by BPAC (2017) and SafeRx. 

(iv) Clozapine levels are reduced by cigarette smoking; however, it is the constituents of smoke, not nicotine itself, that is responsible.  Elevated clozapine levels, up to double baseline, may occur when patients stop smoking and this is not affected by NRT.  If patients stop smoking it is advisable to monitor plasma clozapine levels, dose reduction may be required in conjunction with mental health service advice. Conversely, if a patient starts smoking during treatment, the therapeutic effect of clozapine may be reduced. The plasma concentration of clozapine can also be increased by a high caffeine intake (more than 400mg/day – colas, tea and many energy drinks contain significant amounts of caffeine). Clozapine levels can subsequently decrease by nearly 50% after a 5-day caffeine-free period.

(v)  The article concludes:  Every time a patient comes in, there is an opportunity to query about adverse effects (with a focus on smoking status and bowel habits), check they are taking their medication appropriately, and offer lifestyle advice. Blood test results should be checked and compared with baseline. It is also important to ensure patients are aware of the need for blood tests to be done on the day they are due.  The Porirua Protocol is an evidence-based bowel management regime for patients taking clozapine.  

4.  PAD – best practice and equity

Issue 106 of the Maori Health Review reported a recent retrospective study from the Midland region on prescribing of cardioprotective medications and the impact on survival for patients with peripheral artery disease that undergo intervention.  Findings included:

  • Overall, 80.7% of patients received a prescription for antihypertensive medication, 77.4% for lipid-lowering medication and 89.9% for antithrombotic medication with prescribing of all three noted as ‘best medical therapy’.
  • Patients with concomitant ischaemic heart disease were more likely to be prescribed cardioprotective medication. Women were less likely to be prescribed lipid-lowering medication than men and younger patients were less likely to be prescribed lipid lowering medication than older patients.  Māori men were less likely to be prescribed antiplatelet medication compared with non-Māori men although were more often prescribed antihypertensive agents and no significant difference in statin prescribing.
  • Lipid-lowering and antiplatelet medication showed a survival advantage on univariate analysis, while antihypertensive and anticoagulant medication did not. Best medical therapy was associated with better survival after adjustment for age, sex, end stage renal failure and presence of chronic limb-threatening ischaemia.

On the equity theme, there is a great article from Cook Street Medical Centre in the January edition of GP Voice about their equity journey and outcomes. 

5.  Medsafe monitoring communication

In January Medsafe released a monitoring communication regarding the DPP4 inhibitor vildagliptin (Galvus, Galvumet).  The communication requested reporting to CARM of any patients on the medication being diagnosed with ileus.  While there is insufficient evidence currently to confirm any association between use of DPP4 inhibitors and ileus, the association may have biological plausibility as DPP-4 inhibitors act by inhibiting the breakdown of endogenous glucagon-like peptide-1 (GLP-1), which has a role in inhibition of gastrointestinal motility.

6.  Resource 1:  Pregnancy-related and post-natal depression and anxiety

Online mental health provider, Just a Thought, has launched CBT courses titled Pregnancy Wellbeing and Postnatal Wellbeing for women who experience depression and anxiety during their perinatal journey. The courses are evidence-based and free of charge.  You can refer your patients and follow their progress via the on-line dashboard once you are registered as a clinician with Just a Thought, or the patient can self-access.

7.  Resource 2:  Skin Cancer Symposiums

Educational provider Skin Cancer Symposiums offers a variety of on-line and in-person courses aimed at facilitating accurate and timely diagnosis of skin cancers, particularly melanoma.  They are currently offering a complimentary on-line mini-course on the basics of dermatoscopy and diagnosing melanomas (Register here)  with the goal of the course described as: to facilitate the basic understanding of the visual “red flags” of diagnosing melanoma.  In all of the cases presented, we include clinical and dermatoscopic images. In some, the diagnosis will be evident in the clinical image and reviewing the dermatoscopic image will further reinforce this. In some examples, the diagnosis is only evident in the dermatoscopic image.

8.  Covid vaccine 2024

Manatu Hauora confirmed at the end of December that a vaccine to combat the newer strains of COVID-19 has been approved by Medsafe and will be available to New Zealanders in time for winter 2024.  The COVID-19 XBB.1.5 (Comirnaty® Omicron XBB.1.5) has been approved for the 12+ age group with no plan reported for any changes in current eligibility criteria.   Eligible people are encouraged not to defer booster shots of the existing vaccine if due in view of prevalence of Covid-19 in the community.  While the most prevalent subvariant currently internationally and in NZ is JN.1, the receipt of updated SARS-CoV-2 vaccines containing the monovalent XBB.1.5 spike protein is anticipated to provide protection against JN.1[1].

[1] https://www.idsociety.org/covid-19-real-time-learning-network/vaccines/will-covid-vaccines-continue-to-work-against-jn.1-and-other-new-variants#/+/0/publishedDate_na_dt/desc/