Download robaxin®/robaxin®-750 (methocarbamol tablets, USP)

ROBAXIN- metho carbamo l tablet, film co ated
Actient Pharmaceuticals, LLC
---------robaxin ® / robaxin® -7 50 (methocarbamol tablets, US P)
Rx Only
DESCRIPT ION
ro baxin® /ro baxin® -750 (metho carbamo l tablets, USP), a carbamate derivative o f g uaifenesin, is a
central nervo us system (CNS) depressant with sedative and musculo skeletal relaxant pro perties.
The chemical name of metho carbamo l is 3-(2-metho xypheno xy)-1,2-pro panedio l 1-carbamate and has
the empirical fo rmula C 11 H15 NO 5 . Its mo lecular weig ht is 24.24. The structural formula is sho wn
belo w.
Metho carbamo l is a white po wder, sparing ly so luble in water and chlo ro fo rm, so luble in alco ho l (o nly
with heating ) and pro pylene g lyco l, and inso luble in benzene and n-hexane.
ro baxin® is available as a lig ht o rang e, ro und, film-co ated tablet co ntaining 50 0 mg o f metho carbamo l,
USP fo r o ral administratio n. T he inactive ing redients present are co rn starch, FD&C Yello w 6 , hydro
xypro pyl cellulo se, hypro mello se, mag nesium stearate, po lyso rbate 20 , po vido ne, pro pylene g lyco l,
saccharin so dium, so dium lauryl sulfate, so dium starch g lyco late, stearic acid, titanium dio xide.
ro baxin® -750 is available as an o rang e capsule-shaped, film-co ated tablet co ntaining 750 mg o f metho
carbamo l, USP fo r o ral administratio n. In additio n to the inactive ing redients present in ro baxin®,
robaxin® -750 also co ntains D&C Yello w 10 .
CLINICAL PHARMACOLOGY
T he mechanism o f actio n o f metho carbamo l in humans has no t been established, but may be due to
general central nervo us system (CNS) depressio n. It has no direct actio n o n the co ntractile mechanism
of striated muscle, the mo to r end plate o r the nerve fiber.
Pharmaco kinetics
In healthy vo lunteers, the plasma clearance o f metho carbamo l rang es between 0 .20 and 0 .8 0 L/h/kg, the
mean plasma eliminatio n half-life rang es between 1 and 2 ho urs, and the plasma pro tein binding rang es
between 4 6 % and 50 %.
Metho carbamo l is metabo lized via dealkylatio n and hydro xylatio n. Co njug atio n o f metho carbamo l also
is likely. Essentially all metho carbamo l metabo lites are eliminated in the urine. Small amo unts o f
unchang ed metho carbamo l also are excreted in the urine.
Special po pulatio ns
Elderly
T he mean (± SD) eliminatio n half-life o f metho carbamo l in elderly healthy vo lunteers (mean (± SD) ag e,
6 9 (± 4 ) years) was slig htly pro lo ng ed co mpared to a yo ung er (mean (± SD) ag e, 53.3 (± 8 .8 ) years),
healthy po pulatio n (1.5 (± 0 .4 ) ho urs versus 1.1 (±0 .27) ho urs, respectively). T he fractio n o f bo und
metho carbamo l was slig htly decreased in the elderly versus yo ung er vo lunteers (4 1 to 4 3% versus 4 6 to
50 %, respectively).
Renally impaired
T he clearance o f metho carbamo l in 8 renally-impaired patients o n maintenance hemo dialysis was
reduced abo ut 4 0 % co mpared to 17 no rmal subjects, altho ug h the mean (± SD) eliminatio n half-life in
these two g ro ups was similar: 1.2 (± 0 .6 ) versus 1.1 (±0 .3) ho urs, respectively.
Hepatically impaired
In 8 patients with cirrho sis seco ndary to alco ho l abuse, the mean to tal clearance o f metho carbamo l was
reduced appro ximately 70 % co mpared to that o btained in 8 ag e- and weig ht-matched no rmal subjects.
The mean (± SD) eliminatio n half-life in the cirrho tic patients and the no rmal subjects was 3.38 (± 1.6 2)
ho urs and 1.11 (± 0 .27) ho urs, respectively. T he percent o f metho carbamo l bo und to plasma pro teins
was decreased to appro ximately 4 0 to 4 5% co mpared to 4 6 to 50 % in the no rmal subjects.
INDICAT IONS AND USAGE
ro baxin® and ro baxin® -750 are indicated as an adjunct to rest, physical therapy, and o ther measures fo r
the relief o f disco mfo rt asso ciated with acute, painful musculo skeletal co nditio ns. T he mo de o f actio n
o f metho carbamo l has no t been clearly identified, but may be related to its sedative pro perties.
Methocarbamo l do es no t directly relax tense skeletal muscles in man.
CONT RAINDICAT IONS
ro baxin® and ro baxin® -750 are co ntraindicated in patients hypersensitive to metho carbamo l o r to any o f
the tablet co mpo nents.
WARNINGS
Since metho carbamo l may po ssess a g eneral CNS depressant effect, patients receiving ro baxin® o r
ro baxin® -750 sho uld be cautio ned abo ut co mbined effects with alco ho l and o ther CNS depressants.
Safe use o f ro baxin® and ro baxin® -750 has no t been established with reg ard to po ssible adverse
effects upo n fetal develo pment. T here have been repo rts o f fetal and co ng enital abno rmalities
following in utero expo sure to metho carbamo l. T herefo re, ro baxin® and ro baxin® -750 sho uld no t be
used in wo men who are o r may beco me preg nant and particularly during early preg nancy unless in the
judgment o f the physician the po tential benefits o utweig h the po ssible hazards (see PRECAUT IONS,
Preg nancy).
Us e In Activities Requiring Mental Alertnes s
Metho carbamo l may impair mental and/o r physical abilities required fo r perfo rmance o f hazardo us
tasks, such as o perating machinery o r driving a mo to r vehicle. Patients sho uld be cautio ned abo ut
operating machinery, including auto mo biles, until they are reaso nably certain that metho carbamo l
therapy do es no t adversely affect their ability to eng ag e in such activities.
PRECAUT IONS
Info rmatio n fo r Patients
Patients sho uld be cautio ned that metho carbamo l may cause dro wsiness o r dizziness, which may impair
their ability to o perate mo to r vehicles o r machinery.
Because metho carbamo l may po ssess a g eneral CNS-depressant effect, patients sho uld be cautio ned
abo ut co mbined effects with alco ho l and o ther CNS depressants.
Drug Interactio ns
See WARNINGS and PRECAUT IONS fo r interactio n with CNS drug s and alco ho l.
Metho carbamo l may inhibit the effect o f pyrido stig mine bro mide. T herefo re, metho carbamo l sho uld be
used with cautio n in patients with myasthenia g ravis receiving anticho linesterase ag ents.
Drug /Labo rato ry T es t Interactio ns
Metho carbamo l may cause a co lo r interference in certain screening tests fo r 5-hydro xyindo leacetic
acid (5-HIAA) using nitro so naphtho l reag ent and in screening tests fo r urinary vanillylmandelic acid
(VMA) using the Gitlo w metho d.
Carcino g enes is , Mutag enes is , Impairment o f Fertility
Lo ng -term studies to evaluate the carcino g enic po tential o f metho carbamo l have no t been perfo rmed.
No studies have been co nducted to assess the effect o f metho carbamo l o n mutag enesis o r its po tential
to impair fertility.
Preg nancy
Teratogenic Effects
Pregnancy Category C
Animal repro ductio n studies have no t been co nducted with metho carbamo l. It is also no t kno wn whether
metho carbamo l can cause fetal harm when administered to a preg nant wo man o r can affect repro ductio n
capacity. ro baxin® and ro baxin® -750 sho uld be g iven to a preg nant wo man o nly if clearly needed.
Safe use o f ro baxin® and ro baxin® -750 has no t been established with reg ard to po ssible adverse
effects upo n fetal develo pment. T here have been repo rts o f fetal and co ng enital abno rmalities
following in utero expo sure to metho carbamo l. T herefo re, ro baxin® and ro baxin® -750 sho uld no t be
used in wo men who are o r may beco me preg nant and particularly during early preg nancy unless in the
judgment o f the physician the po tential benefits o utweig h the po ssible hazards (see WARNINGS).
Nurs ing Mo thers
Metho carbamo l and/o r its metabo lites are excreted in the milk o f do g s; ho wever, it is no t kno wn whether
metho carbamo l o r its metabo lites are excreted in human milk. Because many drug s are excreted in human
milk, cautio n sho uld be exercised when ro baxin® o r ro baxin® -750 is administered to a nursing wo man.
Pediatric Us e
Safety and effectiveness o f ro baxin® and ro baxin® -750 in pediatric patients belo w the ag e o f 16 have
no t been established.
ADVERSE REACT IONS
Adverse reactio ns repo rted co incident with the administratio n o f metho carbamo l include:
Body as a whole: Anaphylactic reactio n, ang io neuro tic edema, fever, headache
Cardiovascular system: Bradycardia, flushing , hypo tensio n, synco pe, thro mbo phlebitis
Digestive system: Dyspepsia, jaundice (including cho lestatic jaundice), nausea and vo miting
Hemic and lymphatic system: Leuko penia
Immune system: Hypersensitivity reactio ns
Nervous system: Amnesia, co nfusio n, diplo pia, dizziness o r lig htheadedness, dro wsiness, inso mnia, mild
muscular inco o rdinatio n, nystag mus, sedatio n, seizures (including g rand mal), vertig o
Skin and special senses: Blurred visio n, co njunctivitis, nasal co ng estio n, metallic taste, pruritus, rash,
urticaria
OVERDOSAGE
Limited info rmatio n is available o n the acute to xicity o f metho carbamo l. Overdo se o f metho carbamo l is
frequently in co njunctio n with alco ho l o r o ther CNS depressants and includes the fo llo wing sympto ms:
nausea, dro wsiness, blurred visio n, hypo tensio n, seizures, and co ma.
In po st-marketing experience, deaths have been repo rted with an o verdo se o f metho carbamo l alo ne o r in
the presence o f o ther CNS depressants, alco ho l o r psycho tro pic drug s.
T reatment
Manag ement o f o verdo se includes sympto matic and suppo rtive treatment. Suppo rtive measures include
maintenance o f an adequate airway, mo nito ring urinary o utput and vital sig ns, and administratio n o f
intraveno us fluids if necessary. T he usefulness o f hemo dialysis in manag ing o verdo se is unkno wn.
DOSAGE AND ADMINIST RAT ION
ro baxin® (metho carbamo l), 50 0 mg – Adults:
Initial do sag e: 3 tablets q.i.d.
Maintenance do sag e: 2 tablets q.i.d.
ro baxin® -750 (metho carbamo l): 750 mg – Adults:
Initial do sag e: 2 tablets q.i.d.
Maintenance do sag e: 1 tablet q.4 h. o r 2 tablets t.i.d.
Six g rams a day are reco mmended fo r the first 4 8 to 72 ho urs o f treatment. (Fo r severe co nditio ns
8 g rams a day may be administered). T hereafter, the do sag e can usually be reduced to appro ximately
4 g rams a day.
HOW SUPPLIED
ro baxin® (metho carbamo l tablets, USP)
50 0 mg tablets are light o rang e, round, film-coated tablets engraved with ROBAXIN 50 0 on the
unscored side and SP above the score on the other side. They are supplied as follows:
Bo ttles of 10 0
NDC 5224 4 -4 29 -10
robaxin ® -750 (methocarbamol tablets, USP)
750 mg tablets are o rang e, capsule-shaped, film-coated tablets engraved with ROBAXIN 750 on one side
and SP on the other. They are supplied as follows:
Bottles of 10 0
NDC 5224 4 -4 4 9 -10
Store at controlled room temperature, between 20 °C and 25°C (6 8 °F and 7 7 °F).
Dis pens e in tight container.
Distributed by:
Actient Pharmaceuticals, LLC
Lake Forest, Illinois 6 0 0 4 5
Printed in USA
L4 4 4 9 F
Rev1 0 3/11