Muscle relaxants are methocarbamol, carisoprodol, orphenadrine, Chlorzoxazone, Chlormezazone, Valethemate, Baclofen, Tizanidine.

Methocarbamol:- It causes skeletal muscle relaxant by preferential blockade of poly synaptic spinal reflexes. It is rapidly absorbed from gI tract, metabolized in liver and excreted in urine as glucoronide and sulphate conjugates of its metabolites. Small amount is excreted in faeces.

Special Precautions:- Impairment of hepatic and renal function. Indications:- Skeletal muscle spasm in surgery,  Orthopedics procedures, neurological diseases, Tetanus. Dosage:- Adults: Maximum daily dose is 3 gm for not more than 3 days except in tetanus. Tablet 1.5gm 3-4times daily. Maintainance;- 1gm 4 times a day. Inj. 1gm daily. severe cases:- 1-2 gm i.v/i.m & 1.5 gm tabs 6hourly for 24-48 hours. later reduce to 0.15 to 1 gm 4 hourly. Tetanus:- 2-3 gms i.v. 10-15 minutes . The 2gms amps every 6 hours until oral therapy can be started by dose of 18-40 tabs of 500mg daily in divided doses  4-6 hourly by nasogastric tube. Brand name:- Flexinol ( Methocarbomol 400mg+ paracetamol 325 mg)

Carisoprodol:- It is used for treatment of mucous spasm. It has antipyretic and weak anti adrenergic activity. It is absorbed from GI tract, metabolized in liver and excreted in urine as metabolites including Meprobromate.

Indications:- Muscular-skeletal disorders. Dosage:- Adults: 350mg thrice daily. Children:- not recommended below 12 years. Brand Name:- carisoma : (350mg tab) carisoprodol. Carisoma compound: ( carisoprodal 75 mg+ paracetamol 375mg,+ caffeine 32 mg tab.) Somaflam:- (Carisoprodal 350mg + Ibuprofen 400mg tabs)

Orphenadrine:- It is a centrally acting muscle relaxant drug. With administration of 100mg of orphenadrin, peak plasma concentration are achieved within two hours. Half life is 14hours for the parent drug. and 2-25 hours for metabolites. excretion is via urine & faeces.

Special Precautions:- Urinary retention, impaired hepatic or renal function, tachycardia, GI ostruction. Caution while driving or operating machine.

Indications:- Muscular skeletal disorders, traumas, Sports injuries, low back tension, headache, sprains& strains, parkinsonism, including drug induced.

Dosage;- Adults: Initially 50mg thrice a daily increasing by 50mg every 2-3 days. Maintainance: usually 100-300mg daily. Max:- 400mg daily.  Brand Name: Orphamol ( orphenadrine 35 mg + Paracetamol 450mg)

Chlorzoxazone:- It is a skeletal muscle relaxant. After oral administration, it is rapidly & completely absorbed. It is metabolized in liver and excreted in urine as glucuronide.

Special precautions:- stop therapy if liver dysfunction occurs.

Indications:- painful skeletal muscle spasms.  Dosage:- Adults: 250-750mg 3-4 times daily. children:- 125-500mg, 3-4 times daily. Brand names:  powergesic MR ( chlorzoxazone 500mg + diclofenec sodium 50mg + paracetamol 500mg)  Triactin: ( chlorzoxazone 250mg+paracetamol 500mg,+ Diclofenac sodium 50mg) Spontrel:-( Chlorzoxazone 250mg +Ibuprofen 400mg + Paracetamol 300mg) Systaflam:- Chlorzoxazone 500mg + acetaminophen 325 mg+ Diclofenac sodium 50mg.

Chlormezanone:- Ir acts mainly at the level of spinal cord by producing blocked of poly synaptic reflexes. Special precautions:- Impaired hepatic or renal function.

Indications:- Painful muscle spasm associated with trauma, lumbago, inflammatory & degenerative processes, Neuritic vasomotor pain, premenstrual tension, dysmenorrhoea, musculo skeletal disorders.

Dosage;- 100-200mg thrice a daily. children:- 50-100mg 3-4 times daily.

Preparation are available in combination with other analgesic & inflammatory drugs e.g.Ibuprofen, paracetamol, diclofenac sodium., actaminophen, nimusulide. which are used for treatment of lumbago, inflammatory degenerative processes, osteoarthritis, fibrositis, trauma, involving muscle ligaments & tendons, myositis, neurotic vasomotor pain, trauma associated with inflammation and spasm. Brand name:- Flagonpc ( chlormazanone-100mg + paracetamol 325mg + diclofenac sodium 50mg)

Valethamate:- It is a smooth muscle relaxant.

Indications:- Smooth muscle spasm specially in delayed dilation of cervix.

Dosage:- Adults:- when os-uteri has dilated 2-4 cm, 8mg by deep i.m if required repeat after 20minutes. children: - Not applicable. Brand name :- valosin inj. ( Valthamate 8mg sodium/ml amp of 1ml) Epidosin inj.:- (valthamate bromide 8mg/ml amp of 1ml)

Baclofen:- It is an effective antispastic drug.

Mode of action:- Exact mechanism of action is not known. it inhibit mono synaptic & poly synaptic reflexes tranmissionat spinal leval probaly by stimulating GABA receptors which in turn inhibit the release of glutamate & Asparatate. After oral administration it is rapidly & completely absorbed . it is eliminated from the primarily by kidneys in an unexchanged form.The main metabolites is pharmacologically active.

Indications:- It is most effective in treatment of spasticity in multiple sclerosis. Spastic condiction occuring in spinal cord diseases of degenerative , traumatic, infections of unknown origin like amytropic lateral sclerosis, transverse myelitis, spastic spinal paralysis. Muscle spasticity of cerebral origin e.g. Cerebral palsy.

Dosage:  Adults: start with 15mg /day. Maintainance dose range 30-75mg/day in divided doses. patient under haemodialysis 5mg/day. Children:- 0.75-2mg/kg body weight/day in divided doses. Brand name: Lioresal tablet: ( Baclofen 25 mg )

Tinazidine:- It is centrally acting alpha 2 agonist structurally similar to clonidine.

Special precautions:- Renal & hepatic impairment, driving vehicle & operation hezardour machinary.

Indications:- Painful muscle spasm associated with static and functional disorders of spine following surgery for disc collapse, osteoarthritis of hip.

Dosage:- muscle spasm:- 2mg thrice a day. Spasticity:- maximum initial dose 6mg /day in divided doses, increase stepwise to 12-36mg/day  Brand name:- Proxyvon MR Tablet:-( tinazidine 2mg,+ Nimusulide 100mg