Prescribing - Legislation, the BNF, & Adverse Drug Reactions

• Legislation:

  • The Medicines Act (1968)
  • =overall legislative framework for all medicines
  • Governs the manufacture and supply of medicines
  • The Misuse of Drugs Act (1971)
  • Covers 'dangerous or otherwise harmful' drugs, with the potential for diversion and misuse
  • Intended to prevent the non-medical use of certain drugs
  • Regulates what are termed controlled drugs
  • The human medicines regulations 2012
  • Authorisation of medicinal products for human use
  • Replace most of Medicines act, but mirror it
  • EU directives
  • Govern pharmacovigilance for those holding marketing authorisation
• Medicines Act (1968) defines medicines as follows:

  • General Sales List (GSL)
  • No pharmacist on site
  • Control: strength, use, pharmaceutical form and route of administration
  • Eg paracetamol in Tesco's
  • Pharmacy medicines (P) - from pharmacy
  • Over The Counter (OTC)
  • No prescription needed - paracetamol again
  • Need pharmacist present eg chloramphenicol eye drops
  • Prescription Only (POM)
  • Eg antibiotics, LA
• Licensed vs off-label - before any medicine onto UK market requires MHRA to issue a license:

  • MHRA (Medicines and Healthcare products Regulatory Agency) issues if:
  • Clinical trials prove efficacy for that particular condition
  • Side effects acceptable
  • Meets safety and quality standards
  • BUT off-license prescribing possible
  • More demands on prescriber
  • Eg AEDs (anti-epileptic drugs) for Trigeminal Neuralgia
  • BUT unlicensed medication administration possible: normally in trial OR early access to medicines scheme (EAMS)
• Misuse of Drugs Act (1971):

  • Controls following aspects of 'dangerous or otherwise harmful' drugs: export, import, supply and possession
  • Makes all aspects involving these drugs illegal - except under certain provisions stated in the act
  • Labels them as "controlled drugs"
• Controlled drugs (not exhaustive):

  • Class A: cocaine (and crack), ecstasy, heroin, LSD, methadone, processed magic mushrooms and any Class B drug which is injected. More potent opioids e.g. Morphine, Methadone
  • Class B: amphetamine, barbiturates, codeine and currently cannabis (was previously Class C up to 2009). Less potent opioids e.g. Codeine, DHC.
  • Class C: mild amphetamines, anabolic steroids and minor tranquilisers. BDZs, Ketamine, Buprenorphine, Tramadol
  • Class A drugs are treated by the law as the most dangerous

  
• Professional obligations: GDC - Standards for dental professionals (2013)

  • 4.1.1 ...must make & keep complete & accurate patient records, including...up-to-date medical history, each time...you treat patients.
  • 7.1 ...must provide good quality care based on current evidence & authoritative guidance
  • 7.1.2 If you deviate from established practice & guidance, you should record the reasons why & be able to justify your decision.
  • 7.2 Work within your knowledge, skills, professional competence and abilities.
• Professional obligations: GDC - Standards for dental professionals (2013) - Addendum issued:

  • Prescribing medicines = integral aspect for many treatment plans
  • Prescribe within your competence & keep accurate records
  • Must have an understanding of current relevant medical history, in order to prescribe safely. If in doubt => contact GMP or other
  • Can prescribe any medicine from the British National Formulary (BNF) on a private prescription - only prescribe medicines to meet the identified dental needs of your patients
• Professional obligations: GDC - Standards for dental professionals (2013) - Addendum issued:

  • Must not prescribe medicines for yourself
  • Other than in emergencies, you should not prescribe medicines for anyone with whom you have a close personal relationship
  • Only use remote means to prescribe medicines for dental patients if there is no other viable option and it is in their best interests
• Prescriptions - requirements:

  • Written in ink or otherwise indelible
  • Dated
  • Full name and address of pt
  • Date of birth preferable but essential for <12s (include months too)
  • Signed in ink by prescriber
  • Practitioner's address
  • Name and preparation
  • Avoid decimal points e.g. 500mg NOT 0.5g
  • State frequency and dose
  • Quantity
  • English without abbreviation is preferred though Latin abbreviations are sometimes used (BNF lists these)
  • OD (once daily), BD (twice daily), TDS (three times daily), QDS (four times daily)

  
• Prescription for controlled drug:

  • Handwritten by prescriber
  • Total quantity of drug in figures and words - eg "Total amount of morphine two hundred milligrams (200mg)"
  • Endorsed with words "for dental treatment only"
• Adverse drug reactions in dentistry:

  • Unwanted effects on oral structures
  • Tetracycline staining of teeth
  • Lichenoid reactions - antihypertensives
  • Oral ulceration - nicorandil
  • Unwanted effects on oral function
  • Dry mouth (xerostomia) - diuretics
  • Interference with dental treatment
  • Post-extraction haemorrhage with anticoagulants
• Adverse drug reactions in dentistry - drug interactions:

  • Pharmacokinetic
  • Presence of one drug affects the concentration of another drug at its site of action by altering:
  • Absorption - LA and adrenaline
  • Distribution - warfarin and aspirin
  • Metabolism - LA and beta-blockers
  • Excretion - penicillin and probenecid
• Adverse drug reactions in dentistry - drug interactions:

  • Pharmacodynamic
  • Drug effect is influenced without its concentration at the site of action being affected
  • Agonist
  • Beneficial - co-trimoxazole
  • Adverse - sedatives and alcohol
  • Antagonist
  • Beneficial - flumazenil and midazolam
  • Adverse - salbutamol and beta-blockers