Baclofen
Indications
Baclofen is used for:
Pain, Chronic muscle spasticity, Multiple sclerosis, Spasm, Stiffness, Low back pain
Adult Dose
Oral
Spasticity
Adult: Initially, 5 mg tid for 3 days increased to 10 mg tid for 3 days, then in similar increments and intervals until either 20 mg tid is reached or until desired effect is obtained. Max: 80 mg daily.
Elderly: Initiate with lower doses.
Child Dose
Oral
Spasticity
Child: 0.75-2 mg/kg daily. May initiate with 2.5 mg 4 times daily, increased gradually every 3 days until desired effect is obtained.
Maintenance: 6-10 yr: 30-60 mg daily; 2-6 yr: 20-30 mg daily; 12 mth-2 yr: 10-20 mg daily. Max: >10 yr: 2.5 mg/kg daily.
Renal Dose
Renal impairment: Dose reduction may be required.
Administration
Should be taken with food.
Contra Indications
Hypersensitivity. Active peptic ulcer disease.
Precautions
Cerebrovascular disorders, epilepsy, severe psychotic disorders, confusional states, history of peptic ulcer, resp depression, diabetes (DM), hepatic or renal impairment, elderly, pregnancy. Avoid sudden withdrawal.
Lactation: Enters breast milk in small amounts; not recommended
Pregnancy-Lactation
Pregnancy
There are no adequate data on the developmental risk associated with the use in pregnant women
Oral administration of baclofen to pregnant rats resulted in an increased incidence of fetal structural abnormalities at a dose which was also associated with maternal toxicity
Clinical considerations
May increase the risk of late-onset neonatal withdrawal symptoms
Animal data
Baclofen given orally has been shown to increase the incidence of omphaloceles (ventral hernias) in fetuses of rats given ~13 times on a mg/kg basis, or 3 times on a mg/m2 basis, the maximum oral dose recommended for human use; this dose also caused reductions in food intake and weight gain in the dams
This abnormality was not seen in mice or rabbits
Lactation
At recommended oral doses, baclofen is present in human milk
There are no human data on the effects of baclofen on milk production
There are no adequate data on the effects of baclofen on the breastfed infant
Withdrawal symptoms can occur in breastfed infants when maternal administration is stopped, or when breastfeeding is stopped
Consider developmental and health benefits of breastfeeding along with the mother’s clinical need and any potential adverse effects on the breastfed infant or from the underlying maternal condition
Interactions
Hypotensive effect may be increased with antihypertensives. Concomittant use with levodopa in Parkinson patients may result in confusion, agitation, hallucinations.
Potentially Fatal: CNS depressants and alcohol may potentiate CNS effects.
Side Effects
Side effects of Baclofen :
>10%
Drowsiness, transient (10-63%), Dizziness (5-15%), Nausea (4-12%), Confusion (1-11%)
1-10%
Headache (4-8%), Insomnia (2-7%), Constipation (2-6%), Urinary frequency (2-6%), Fatigue (2-4%)
<1%
Abdominal pain, Ankle edema, Anorexia, Ataxia, Blurred vision, Chest pain, Coordination disorder, Depression, Diarrhea, Dry mouth, Diplopia, Dysarthria, Dyspnea, Dystonia, Enuresis, Euphoria, Excitement, Hallucinations, Hematuria, Hypotension, Impotence, Miosis, Muscle pain, Mydriasis, Nasal congestion, Nocturia, Nystagmus, Palpitation, Paresthesia, Excessive perspiration, Pruritus, Rash, Rigidity, Seizure, Strabismus, Slurred speech, Syncope, Tinnitus, Tremor, Urinary retention, Vomiting, Weight gain
Potentially Fatal: Respiratory or CV depression, seizures.
Mode of Action
Baclofen is an antispastic. It inhibits both monosynaptic and polysynaptic reflexes at spinal level.