Drugs

Question 1

Tamsulosin

Answer 1

Used to treat BPH
Tamsulosin (selective alpha1 receptor antagonist, which blocks the alpha 1 receptors in the bladder neck, prostate and urethra resulting in relaxation of the smooth muscle. - can also be used to treat kidney / ureter stones

Question 2

Finasteride

Answer 2

Used to treat BPH
Decreases prostate by up to 20%
Decreases vascularity so lower chance of having a bleed
5-alph reductase inhibitor, which decreases DHT

Question 3

Treatment for benign prostatic hyperplasia (BPH)

Answer 3

Finasteride
Tamsulosin

Or treated surgically with a TURP
Trans urethral resection of prostate (scraping away the lobes)
Or laser therapy for big prostates

Question 4

Nitrofurantoin

Answer 4

Common antiobiotic for UTI

• Works by damaging ribosomal proteins & DNA causing inhibition of protein and cell wall synthesis

• Active against
• E.coli,enterococcus,klebsiella,enterobacter,staphylococcus
species
• Rapidly absorbed by the GIT tract, max urinary excretion after 2-4 hours, 40-45% of the dose recovered in the urine
• Food enhances absorption
• Only available as tablets and suspension

• Dose of nitrofurantoin is 50mg QDS or 100mg MR BD
• Caution in renal impairment < 45mL/min/1.73m2
• Can use with care if 30-44 mL/min/1.73m2 (for 3-7 days)

• Side effects
• Acute pulmonary disease ,peripheral neuropathy ,nausea, blood
disordered such as agranulocytosis
• Can colour urine yellow or brown
• Can cause false positive urinary glucose on testing

• Monitoring
• Only if on long term therapy (LFTS, FBC, Chest X ray)

Question 5

Trimethoprim

Answer 5

Trimethoprim
Common UTI antibiotics

• Trimethoprim is a dihydrofolate reductase inhibitor which affects the nucleoprotein metabolism of micro-organisms by interference in the folic-folinic acid systems.

• Active against
• Gram-positive&aerobicGram-negativeorganisms,including
enterobacteria, E.coli, Proteus,

• Rapid & almost complete absorption form GIT. Peak conc 4 hours after dose
• 40-60% dose excreted unchanged in the urine with metabolites (risk of accumulation with renal impairment)

Prescribing advice
• Dose is 200mgnBD
• Caution in renal impairment
• use half normal dose after 3 days if eGFR15-30mL/min/1.73m2
• Use half normal dose if eGFR <15 mL/min/1.73 m2
• Contraindicated in pregnancy & blood dyscrasias

• Side effect
• Nausea, vomiting, skin reactions, hyperkalaemia

• Drug interactions
• Digoxin, phenytoin (increases drug levels)
• Ciclosporin (increase nephrotoxicity of trimethoprim)
• METHOTREXATE

Question 6

Amoxicillin

Answer 6

Amoxicillin
• Amoxicillin works by weakening the bacterial cell wall, which is usually followed by cell lysis and death.
• Broad spectrum but lots of resistance!

• Dose
• Typically500mgTDS
• Reduce dose if renal impairment eGFR< 30mL/min/1.73m2

• Side effects
• Nausea,skin reactions
• Interactions
• Methotrexate (amoxicillin can reduce the excretion)
• Warfarin (amoxicillin can increase the INR)
• Allopurinol (risk of skin rashes)

Question 7

Cefalexin

Answer 7

Cefalexin
• Inhibits bacterial cell wall synthesis
• Broad spectrum- but increased risk of c diff

• Dose
• Typically500mgTDS
• Renal impairment
• Maximum of 250mg TDS if eGFR < 10 mL/min/1.73m2

• Cautions
• Hypersensitivitytopenicillins
• Side effects
• Nausea,diarrhoea(riskofantibioticassociatedcolitis)
• Not known to be harmful in pregnancy

Question 8

Ciprofloxacin

Answer 8

• Works by inhibiting enzymes required for bacterial DNA replication, transcription, repair and recombination.
• Board spectrum

• Active against gram+ve and gram–ve including pseudomonas
• Peak concentration after 1-2 hours and largely excreted unchanged in the urine
• Reserved for ascending UTIs or pyelonephritis

• Dose
• Oral500-750mgBD
• IV400mgBD
• Reduce dose in renal impairment
• Several significant interactions
• Avoid milk product at the same time as oral dose

Question 9

Co-amoxiclav (amoxicillin & clavulanic acid)

Answer 9

Co-amoxiclav (amoxicillin & clavulanic acid)
• Same as amoxicillin but clavulanic acid inactivates some beta-lactamase enzymes thereby preventing inactivation of amoxicillin.
• Clavulanic acid alone does not exert a clinically useful antibacterial effect.

• Broadspectrum

• Dose
• Oral500/125mgTDS
• IV1.2gTDS
• Renalimpairment,reducedoseifeGFR<30mL/min/1,73m2
• Contra-indicated in penicillin allergies

• Side effect
• Nausea, diarrhoea, cholestatic jaundice

• Interactions
• Methotrexate, Warfarin, Allopurinol

Question 10

Gentamicin

Answer 10

Gentamicin
Requires a nomogram to manage and monitor dosage
• Works by inhibiting protein synthesis in susceptible bacteria by irreversibly binding to 30S ribosomal subunits
• Broad spectrum - used a lot in ED due to covering gram positive and negative
• Active against E.coli,Klebsiellaspp,Proteusspp,Pseudomonas
aeruginosa, Staphylococci, Enterbacter spp, etc

• Not absorbed from GIT
• IV doses only
• Reduce dose if renal impairment and monitor very closely

• Contra-indications
• Allergy to gentamicin, myasthenia gravis

• Side effects
• Ototoxicity, nephrotoxicity, peripheral neuropathy
• Significant drug interactions
• Avoid other nephrotoxic drugs

Question 11

Carbapenems- Meropenem & ertapenem

Answer 11

• Inhibit bacterial cell wall synthesis
Only microbiologists can prescribe

• Broad spectrum
• Active against gram +ve and gram –ve bacteria
• Not absorbed orally

• Meropenem
• IV500mg-1gTDS
• ReducedoseifeGFR<50mL/min/1.73m2

• Ertapenem
• IV1gdaily
• ReducedoseifeGFR<30mL/min/1.73m2

• Side effects: rashes, seizures
• Interactions: sodium valproate, valproic acid

Question 12

Which of the following would you prescribe in a patient with an allergy to penicillin (rash, not anaphylaxis)?

• Ciprofloxacin
• Flucloxacillin
• Augmentin®
• Cefalexin
• Meropenem
• Tazocin®
• Doxycycline
• Clarithromycin

Answer 12

Without hesitation:
Ciprofloxacin
Clarithromyocin
Doxycycline

With caution:
Cefolexin
Meropenem

Avoid:
Tazosin
Augmentin
Flucloxacillin