Clarithromycin for children

C LARITHRO MY CIN AND AZITHRO MY CIN ARE THE FIRST TWO semi syn thetic mac rolides to be li censed in Can ada. Re cently, a liq uid sus pen sion of clarithro my cin has been li censed for use in chil dren. Clarithro my cin and azithro my cin have sev eral ad van tages over eryth ro my cin, in clud ing • longer half-life, allowing onceor twice-daily dosing; • greater bioavailability after oral doses; • lower incidence of the side effects abdominal pain, nausea and vomiting; • wider spectrum of antimicrobial activity.

semi syn thetic mac rolides to be li censed in Can ada. Recently, a liq uid sus pen sion of clarithro my cin has been licensed for use in chil dren.
Clarithro my cin and azithro my cin have sev eral ad van tages over eryth ro my cin, in clud ing • longer half-life, allowing once-or twice-daily dosing; • greater bioavailability after oral doses; • lower incidence of the side effects abdominal pain, nausea and vomiting; • wider spectrum of antimicrobial activity.

PHARMACOLOGY
Clarithro my cin is well ab sorbed and the ex tent of ad sorption is not sig nifi cantly al tered when ad min is tered with food (1). Ab sorp tion of the liq uid sus pen sion in chil dren ap pears com pa ra ble with that in adults re ceiv ing cap sules. Clarithromy cin is con cen trated in cells and tis sues pro vid ing lev els greater than se rum lev els in the mid dle ear fluid and in lung tis sue (2). Ap proxi mately a third of the drug is ex creted by the kid ney and the rest is me tabo lized in the liver. Its ma jor metabo lite, 14-hydroxy clarithro my cin, also has an ti mi cro bial activ ity, be ing about half as ac tive as clarithro my cin, ex cept for Hae mo phi lus in flu en zae, against which it is more ac tive (3). Its long half-life per mits a twice-daily dos ing sched ule. The rec om mended dose for most in di ca tions is 7.5 mg/kg bid.

ANTIMICROBIAL ACTIVITY
Clarithro my cin has good ac tiv ity against: group A strep tococ cus, Strep to coc cus pneu mo niae, Mo rax ella ca tar rhalis, Myco plasma pneu mo niae, Bor de tella per tus sis, Le gionella pneu mo phila, Chla my dia pneu mo niae, Chla my dia tra cho matis, Neis se ria gon or rhoeae, Heli co bac ter py lori and Propio nibac te rium ac nes.
It has good ac tiv ity, but with more vari able mini mum in hibi -tory con cen tra tions, against: H in flu en zae, me thicillinsusceptible Staphy lo coc cus au reus, cam py lo bac ter, some atypi cal my co bac te ria in clud ing My co bac te rium avium complex (MAC) and My co bac te rium le prae. It is not very ac tive against methicillin-resistant S aureus, coagulase-negative staphy lo cocci and en te ro cocci.
S pneu mo niae re sis tant to clarithro my cin have al ready been re ported (4).

CLINICAL TRIALS IN CHILDREN
Clini cal tri als in Europe and North Amer ica have shown that clarithro my cin is simi lar in ef fi cacy to other oral an ti bi otics, such as amoxicillin-clavulanate, ce fa clor and amox icil lin, for treat ment of acute oti tis me dia in chil dren six months to 12 years of age (5)(6)(7)(8)(9). Du ra tion of ther apy was seven to 10 days in the North Ameri can tri als and five days in the Euro pean trials. In all tri als clarithro my cin and the al ter na tive an ti bi otic achieved simi lar rates of symp to matic and bac te rial cure.
Clarithro my cin cap sules or sus pen sion are as ef fec tive as peni cil lin V for treat ment of strep to coc cal pha ryn gi tis (10). The eradi ca tion rate of group A strep to coc cus was slightly bet ter with clarithro my cin than with peni cil lin V.
Evi dence from clini cal tri als on the ef fi cacy of clarithro mycin in the treat ment of lower res pi ra tory tract in fec tions in children is not yet avail able.

ADVERSE EFFECTS
In chil dren, ad verse ef fects of clarithro my cin have been infre quent (in com para tive tri als, rates were simi lar to those with amox icil lin) (11). The most com mon ad verse ef fects are gastro in tes ti nal, but they are less fre quent with clarithro my cin than with eryth ro my cin or amoxicillin-clavulanate.

USES OF CLARITHROMYCIN IN CHILDREN
The spec trum of an ti mi cro bial ac tiv ity com bined with a rela tively low rate of ad verse events and the con ven ience of twice-daily dos ing will make clarithro my cin an at trac tive option in the treat ment of res pi ra tory tract in fec tions in chil dren. For atypical mycobacterial infections, clarithromycin is likely to become a first-line agent. In children with AIDS and MAC infection, clarithromycin was well-tolerated but decreased susceptibility to clarithromycin occurred rapidly on therapy (12). Therefore, as with other agents for mycobacteria, clarithromycin for MAC will be useful as one of a combination of agents used for treatment and prophylaxis.

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For adult contacts of children with pertussis, clarithromycin offers a good alternative to erythromycin and may improve compliance because it may be better tolerated than erythromycin.
As with all new an ti bi ot ics, we can ex pect re sis tance to emerge, and re sis tance of S pneu mo niae has al ready been re ported. There fore, ju di cial use of clarithro my cin is es sen tial to en sure that it re mains an ef fec tive weapon against in fections for which it would be the agent of choice.