Doxapram hydrochloride (marketed as Dopram, Stimulex or Respiram) is a respiratory stimulant. Administered intravenously, doxapram stimulates an increase in tidal volume, and respiratory rate. Mechanism of action
Doxapram stimulates chemoreceptors in the carotid bodies of the carotid arteries, which in turn,  stimulates the respiratory centre in the brain stem. Appearance
Doxapram is a white to off-white, odorless, crystalline powder that is stable in light and air. It is soluble in water, sparingly soluble in alcohol and practically insoluble in ether. Injectable products have a pH from 3.5-5. Benzyl alcohol or chlorobutanol is added as a preservative agent in the commercially available injections. Uses
Doxapram is used in intensive care settings to stimulate the respiratory rate in patients with respiratory failure. It may be useful for treating respiratory depression in patients who have taken excessive doses of drugs such as buprenorphine or fentanyl analogues which may fail to respond adequately to treatment with naloxone.It is equally as effective as pethidine in suppressing shivering after surgery.Doxapram has been used as an anesthetic reversal agent when taking care of captive sharks but it must be used with caution since "animals can be extremely excitatory and dangerous under the influence of this drug". Side effects
Side effects include high blood pressure, panic attacks, rapid heart rate, tremor, sweating, and vomiting. Convulsions have been reported. Its use is relatively contraindicated in people with coronary heart disease, epilepsy, and high blood pressure.
Signs and symptoms below are most common in the severe SMA type 0/I:
Areflexia, particularly in extremities
Overall muscle weakness, poor muscle tone, limpness or a tendency to flop
Difficulty achieving developmental milestones, difficulty sitting/standing/walking
In small children: adopting of a frog-leg position when sitting (hips abducted and knees flexed)
Loss of strength of the respiratory muscles: weak cough, weak cry (infants), accumulation of secretions in the lungs or throat, respiratory distress
Bell-shaped torso (caused by using only abdominal muscles for respiration) in severe SMA type
Fasciculations (twitching) of the tongue
Difficulty sucking or swallowing, poor feeding

Causes
Spinal muscular atrophy is caused by a genetic mutation in the SMN1 gene.Human chromosome 5 contains two nearly identical genes at location 5q13: a telomeric copy SMN1 and a centromeric copy SMN2. In healthy individuals, the SMN1 gene codes the survival of motor neuron protein (SMN) which, as its name says, plays a crucial role in survival of motor neurons.