Diabetic Foot infection Flashcards
1
Q
Co-trimoxazole
NB- 480mg = 400mg sulfamethoxazole + 80mg trimethoprim
Indications
A
- Susceptible infections
- Diabetic foot infection
- HAP
- Exacerbation of COPD
- Treatment of PCP
- Prophlaxis of PCP
- Acute prostatitis
2
Q
Co-trimoxazole
Indications
A
- Sulfamethoxazole competitively inhibits the utilisation of para-aminobenzoic acid in the synthesis of dihydroflate by the bacterial cell resulting in the bacteriostasis
- Trimethoprim reversibly inhibits bacterial dihydrofolate reductase (DHFR), an enzyme active in the folate pathway converting dihydrofolate to tetrahydrofolate
- Depending on the conditions this could be bactericidal
- Thus trimethoprim and sulfamethoxazole block 2 consecutive steps in the biosynthesis of purines and therefore nucleic acids essential to many bacteria
- This action produces marked potentiation of activity (synergistic)
- NB- does have the effects of MTX as its affinity for human DHFR is 50,000 times smaller than for bacteria
3
Q
Co-trimoxazole
Warnings
A
- Contraindicated in acute porphyrias
- Cautioned
- Asthma
- Blood disorders
- Infants U6 weeks (except PCP)- due to risk of kernicterus
- Elderly
- G6PD deficiency- risk of haemolytic anaemia
- Inadequate fluid intake
- Predisposition for folate deficiency
- Predisposition for hyperkalaemia
4
Q
Co-trimoxazole
Adverse effects
A
- Infections- Overgrowth fungal
- Metabolism- Hyperkalaemia
- Teratogenic- Do not give in the first/third trimester of pregnancy (folate antagonist)
- Co-trimoxazole is associated with rare but serious blood disorders
- Leucopenia
- Thrombocytopenia
- Eosinophilla
-
Rash
- Stevens-Johnson Syndrome
- Toxic epidermal necrolysis
5
Q
Co-trimoxazole
Interactions
A
- Warfarin- co-trimoxazole potentiates the anticoagulant effect of warfarin via inhibition of metabolism. Sulfamethoxazole also displaces warfarin from albumin. Increase monitoring
- Phenytoin- Co-trimoxazole increases half-life of phenytoin
- Dig- increased dig half life particularly in elderly
- Any med that can cause hyperkalaemia- ACEI, ARB, K-sparring diuretics
- Folic acid
- Azathioprine- increased risk of haematological abnormalities
6
Q
Co-trimoxazole
Monitoring
A
- Monitor Blood counts
- Monitor for Rashes
7
Q
Linezolid
Indications
NB- all indications are under specalist use only
A
- Pneumonia- When other antibacterials e.g. glycopeptide such as vanc can’t be used
- Complicated skin and soft-tissue infection caused by G+ve bacteria- where other agents cant be used
- Cellulitis
- Erysipelas
- Diabetic foot infection
8
Q
Linezolid
MOA
A
- Belongs to oxazolidinone class of antimicrobials
- It has activity against G+ bacteria
- Linezolid selectively inhibits bacterial protein synthesis via a unique MOA
- Specifically binds to a site on the 23S + 50S ribosomal subunit and prevents formation of the 70S initiation complex which is essential for translation
9
Q
Linezolid
Warnings
A
- Cautioned in
- Acute confusion
- Bipolar depression
- Carcinoid tumour
- Elderly- increased risk of blood disorders
- History of seizures
- Phaeochromocytoma
- Schizophrenia
- Thyrotoxicosis
- Uncontrolled Hypertension
- Close observation- Unless close observation of BP occurs this should be avoided in uncontrolled HTN, Phaeochromocytoma, carcinoid tumour, thyrotoxicosis, etc
10
Q
Linezolid
Adverse effects
A
- Infection- Candidiasis
- Blood disorders- Leucopenia, thrombocytopenia
- CNS- headache, Taste disturbances
- Hepatobiliary- Abnormal LFT, increased bilirubin
- Renal- Increased BUN
- Optic and peripheral neuropathy- Visual impairment
- Seizures-
11
Q
Linezolid
Interactions
A
- MAOI
- Potentials interactions producing elevation of BP- adrenaline, pseudoephedrine
- Potential serotinergic interactions- Risk of serotonin syndrome
- Use of tyramine-rich foods
12
Q
Linezolid
Monitoring requirements
A
- Monitor full blood count- Including platelet count
13
Q
A
