Cotrimoxazole

Chancroid [Ref: Katzung 11/e p. 818; K.D.T. 6/e p. 686]

Cortrimoxazole in Typhoid

• Initially cotrimoxazole was an effective alternative to chloramphenicol. However, in many areas resistant S. typhi have appeared and now it is seldom used.

Cotrimoxazole in chancroid

• Cortrimoxazole for 7 days is a 3^rd choice inexpensive alternative to ceftriaxone, erythromycin or iprofloxacin.

Cotrimoxazole

• It is a combination of sulfonamide (sulfamethoxazole) and trime- thoprim in the ratio of 1 :5.
• Cotrimoxazole was claimed to be more effective than either of its components individually in treating bacterial infections.
• Because of its associated greater incidence of adverse effects including allergic responses its widespread use has been restricted in many countries to very specific circumstances where its improved efficacy is demonstracted.

Uses of Cotrimoxazole

Upper and lower respiratory tract infections

–  Exacerbations of chronic bronchitis

– For otitis media and sinusitis.

– It should never be used for streptococcal pharyngitis.

Urinary tract infections

–Uncomplicated cystitis in non pregnant women. Especially valuable for chronic and recurrent cases.

–  Prostatitis (cotrimoxazole is concentrated in goodamounts in prostate)

Pneumocystic carinii pneumonia

-Drug of choice next to pentamidine for the treatment and prophylaxis of pneumonias caused by Pneumocystic Jirovecci (commonly seen in imtnunocompromised patients including those suffering from HIV/AIDS).

Other conditions where cotrimoxazole finds its use.

-Listeria monocytogens infections

– Meliodosis – Shigellosis

– Traveller’s diarrhoeas (E. coli, Campylobacter, Shigella, Y. enterocolitica)

– Prophylaxis of cerebral toxoplasmosis

– Whipple’s disease

– Salmonella (typhoid)         initially it was responsive but now resistant strains have emerged.

– Chancroid

According to K.D.T.

–      Cotrimoxaxole can be used in both chancroid and typhoid.

According to Harrison (18/e)

Cotrimoxazole is used in Typhoid but it is not used in chancroid.

Antiobiotic therapy in typhoid Empirical

• Ceftriaxone
• Azithromycin

Fully susceptible

• Ciprofloxacin
• Amoxicillin
• Chloramphenicol
• Cotritnoxazole

Multidrug resistant

• Ciprofloxacin
• Ceftriaxonl
• Azithromycin

Nalidixic acid resistant

• Ceftriaxone
• Azithromycin
• High dose ciprofloxacin

Treatment of chancroid

• Ciprofloxacin
• Ceftriaxone
• Azithromycin

5:1

• HIV infected adults with CD4
• or CD4
• or  WHO clinical stage 3 or 4 irrespective of CD4.

All the choices have risk of clinical hemolysis in G6PD. Definite risk is seen with Cotrimoxazole only, Others have either possible or doubtful risk.

Ref: Harrison 18th edition, Page 879.

Ans. is ‘c’ i.e., 5 : 1

o Optimal synergy in case of most organism is exhibited at a concentration ratio of Sulphamethoxazole 20: Trimethoprim 1 (This ratio is obtained in plasma when two are given in a dose ratio of 5:1).

Ans. is ‘c’ i.e., None > Chancroid

o Actually cotrimoxazole is used in all conditions provided in options.  

o Some guides have given chancroid as the answer. However, many text-books of (KDT, Satoskar, recent advances in pharmacotherapeutics, Evidence based medicine, and many others) have mentioned that cotrimoxazale is used in chancroid.

o Amongst the given options,i will also go for chancroid as Harrison (18^th/e-1109) has not mentioned cotrimoxazole for the treatment of chancroid.

Ans is ‘a’ ie. Cotrimoxazale 

• Don’t get misled by this statement given in O.P. Ghai – “Operative correction of VUR is indicated in pts. with -persistent severe (grade IV or V) reflux”.
• This statement does not mean that any pt. with grade IV & V reflux will be given surgical management and rest medical management. Treatment is not so clear-cut.
• The choice b/w medical or surgical modality is based on certain principles (go through the following text to understand it).

The below given explanation is a bit lengthy. Bear with me for giving such a long text, as it is one of the most important but less read topic (UG books do not give sufficient information on its treatment).

This explanation will help you to tackle any future question on t/t of VUR with different patient profile (as t/t changes with grades as well as age of the patient)

• Vesicoureteral reflux (VUR)
• is the retrograde flow of urine from the bladder to the ureter and the renal pelvis

Complications of VUR

• Reflux predisposes to renal infection (pyelonephritis) by facilitating the transport of bacteria from the bladder to the upper urinary tract.
• The inflammatory reaction caused by a pyelonephritic infection may result in renal injury or scarring.
• Extensive renal scarring impair renal function and may result in renin mediated hypertension, reflux nephropathy, renal insufficiency, end stage renal disease, reduced somatic growth and morbidity during pregnancy.
• Treatment
• The goals of t/t are to prevent pyelonephritis, renal injury, and other complication of reflux.
• Treatment modality is either medical or surgical.
• Medical therapy

– is based on the principle that reflux often resolves over time and the antibiotics maintain urine sterility and prevent infection and complication while awaiting spontaneous resolution.

• Surgical therapy :

– the basis for surgical therapy is that in selected children, ongoing reflux has caused or has significant potential for causing renal injury.

• The decision to do medical or surgical t/t is based on certain principles and parental, patient preferences.
• Below is given a chart listing the treatment recommendation for VUR.
• Before going through the chart lets see the basic principles on which this chart is based ‑With bladder growth and maturation, there is tendency for reflux to resolve or improve over time. Lower grades of reflux are much more likely to resolve than are higher grades.

For grades I & II reflux, the likelihood of resolution is similar irrespective of age at diagnosis and whetner if it unilateral or bilateral.

• For grade III & IV a younger age at diagnosis and unilateral reflux generally are associated with a higher rate of spontaneous resolution.
• Grade V reflux rarely resolves.
• The mean age for reflux resolution is 6 – 7 yrs.
• Reflux is unlikely to cause any renal injury in the absence of infection.

Answer is B (Cotrimoxazole):

Trimethoprim/sulfamethoxazole or Cotrimoxazole is the drug of choice for all firms of Pneumocystis Pneumonias.

‘Trimethoprim-Sulfamethoxazole which acts by inhibiting folic acid synthesis is considered the drug of choice for all forms of Pneumocystis Pneumonias. Therapy is continued for 14 days in Non-HIV-Infected patients and for 21 days in HIV-Infected patients’ – Harrison 18th/1672

Ans. is ‘c’ i.e., Doxycycline is effective against legionella