Download SCP 10 SHARED CARE PROTOCOL Tenofovir Clinical Indication

SCP
10
SHARED CARE PROTOCOL
Tenofovir
Clinical Indication: For use in chronic hepatitis B infection
Version 1: Sept 2014
due for review: August 2016
Introduction
Shared Care
A shared care protocol is used to facilitate the sharing of care and transfer of prescribing. This would
usually take place once the patient’s condition is stable; the patient is demonstrably benefiting from the
treatment and is free from any significant side effects. GPs should only take on the prescribing when
they are confident in the use of the drug, in the context of the protocol. Contingency plans must be in
place to enable the patient to receive the recommended treatment, should the GP decline to prescribe.
Indication for Therapy
Tenofovir is a nucleoside reverse transcriptase inhibitor. It inhibits viral polymerase by directly
competing with the natural deoxyribonucleotide substrate and after incorporation into
deoxyribonucleic acid (DNA), by DNA chain termination. It is licensed for the treatment of
chronic hepatitis B virus (HBV) in adults with compensated liver disease, with evidence of
active viral replication, persistently elevated serum alanine aminotransferase (ALT) levels and
histological evidence of active inflammation and/or fibrosis.
Within NHS Borders, tenofovir will be used in patients with active chronic hepatitis B infection
e-antigen positive and negative as indicated by at least 2 out of following 3 criteria:
HBV DNA (>2000 IU/mL)
persistently abnormal ALT values (>1.3 x upper limit of normal (ULN))
liver biopsy showing chronic hepatitis and fibrosis
Preparations Available
Tenofovir is available as a film coated tablet containing 245mg of tenofovir disoproxil.
Recommended Dosage and Administration
The recommended dose is 245mg once daily taken orally with food to increase absorption
and bioavailabilty. Tenofovir is eliminated by renal excretion and the exposure to tenofovir
increases in patients with renal dysfunction. There is limited data available on the use of
tenofovir in renal impairment and therefore it should only be used if the potential benefits
outweigh the potential risks. Renal function and serum phosphate should be measured
regularly, particularly in patients at risk of renal impairment. The dose of tenofovir should be
adjusted in renal impairment. This should be done in discussion with hospital consultant
This table is for information only - seek advice from secondary care
Creatinine Clearance (mL/min)
>50
30-49
10-29
<10 and non-haemodialysis
Haemodialysis (give dose after HD)
Tenofovir dose
245mg daily
245mg every 48 hours
245mg twice weekly
Not recommended
245mg weekly
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Cost
The estimated cost of 30 days treatment is £240 at normal dose. The optimal duration of
therapy in unknown
Pregnancy and Lactation
The effect of tenofovir on the unborn foetus is unknown at present. Therefore it is
recommended that woman of childbearing potential should use effective contraception during
treatment. There is limited data on tenofovir exposure during pregnancy and therefore
tenofovir should not be used during pregnancy unless absolutely necessary. Tenofovir has
been shown to be excreted in human milk. There is insufficient information on the effects of
tenofovir in newborns/infants; tenofovir is not recommended during breastfeeding. Any
patients wishing to breast feed whilst taking tenofovir should be referred to consultant for
specialist advice.
Shared Care Responsibilities
Aspects of Care for which the Consultant is responsible
 Initiate prescription and provide initial 3 month supply of medicine
Monitor weight, urea and electrolytes (including phosphate), full blood count, liver
function tests and HBV-DNA levels at clinic visits- results to be communicated to GP
Terminating care with respect to treatment of Hepatitis B infection
Aspects of Care for which the General Practitioner is responsible
 To continue with prescribing once the patient’s treatment is stable
Monitoring of urea and electrolytes (including phosphate), liver function tests and full blood
counts (to stay within normal range) every 3 months.
In this patient group, ALT <70u/mL can be considered normal, however if GP has
any concerns regarding results then this should prompt referral back to
consultant
Sending results to and contacting consultant if concerned about the results if outwith
normal range
 Reporting of adverse reactions to Yellow Card Scotland is the responsibility of both the Consultant
and GP
 https://yellowcard.mhra.gov.uk/
Adverse Effects
Tenofovir should not be administered concurrently with adefovir, didanosine or any other
medicinal product containing tenofovir (Truvada® or Atripla®). As tenofovir is principally
eliminated via the kidney, care should be taken with other medicines that reduce renal
function. The concurrent use of tenofovir with nephrotoxic medicines should be avoided. The
most frequent side effects noted with tenofovir are headache, rash, dizziness, gastrointestinal
disturbance, fatigue, increased creatinine and hypophosphataemia. Rare side effects include
acute renal failure and proximal tubulopathy. For a complete list of adverse effects please
consult summary of product characteristics (www.medicines.org.uk)
Tenofovir is a black triangle drug and any suspected adverse drug reaction should be
reported to MHRA using the Yellow Card system (www.yellowcard.mhra.gov.uk). Any serious
adverse drug reactions should also be reported to the GI Team at BGH
Precautions and Contra-indications
Tenofovir is contraindicated in patients with known hypersensitivity to tenofovir or any of its
excipients. Spontaneous exacerbations in chronic hepatitis B are relatively common and are
characterised by transient increases in serum ALT. After initiating antiviral therapy, serum
ALT may increase in some patients as serum HBV DNA levels decline. In patients with
compensated liver disease, these increases in serum ALT are generally not accompanied by
an increase in serum bilirubin concentrations or hepatic decompensation.
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Patients with cirrhosis may be at a higher risk for hepatic decompensation following hepatitis
exacerbation, and therefore should be monitored closely during therapy. Lactic acidosis,
usually in association with hepatic steatosis, has been reported with nucleoside analogues.
The risk with tenofovir is thought to be low however cannot be excluded. Symptoms include
nausea, vomiting and abdominal pain, nonspecific malaise, loss of appetite, respiratory
symptoms or neurological symptoms. Treatment should be discontinued under consultant
direction. Note that there have been no cases reported in chronic hepatitis B treatment.
Supply
In the community, tenofovir is distributed via Central Homecare Ltd (telephone 01420
543400). Community pharmacies can order direct from this company. The lead time for
delivery is next working day if order placed before 4pm Monday-Friday.
Contact Points
Primary Care Prescribing Team
BGH Pharmacy
Dr Evans BGH
Tel: 01896 827708
Tel: 01896 826783
Tel: 01896 826662
This information was prepared by the physicians and pharmacist in the Liver Unit, Royal Infirmary of Edinburgh and
Regional Infectious Disease Unit Western General Hospital, Edinburgh through liaison with the General Practice
Prescribing Committee and the Drug and Therapeutics Committee, Lothian University Hospitals Division.
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