"Pain Killers" or relievers are the medicines which can reduce or relieves headache,arthritis,sore muscles and many other types of body pains.Every individual responds differently to every pain killer.Prescription of the pain killers occurs when someone has compulsive need to take it for relief and is characterized by the loss of control in a person.Addiction to these can develop symptoms of dependance,tolerance and withdrawal which includes the normal physiological processes in body. 
Pain killers are the drugs or steroids which are associated with dangerous side effects,addiction and it's overdose can be very harmful to any person.There are various types of prescriptions of these pain reducing medicines which are abused-
(1)Opiods-These are the medication given during pain like morphine,codeine
fentanyl and many more which can be taken orally or as powder injected in an injection.
(2)CNS depressants-They are prescribed to treat sleep disorders or anxiety
like Valium,Alprax,Xanax etc which are taken orally.They also slows down the normal nervous system which makes the person to sleep properly.
(3)Stimulants-They are used to treat ADHD.
There are many physical effects caused by the intake of pain killers like- Constipation,Depression,Drowsiness,Euphorbia,Increased blood pressure and irregular heart beat.It also includes long term effects-Vomiting,Muscle and Bone pain and cardiovascular failure which can lead to the death of an individual.It is more effective in women by having a double risk of miscarriage during pregnancy.Women should not depend on them during their menstrual cycle as being anti-inflammatory drug,it can cause harm to female's cycle.Pain killers are very risky for heart patients which could affect heart by taking the consumption of analgesic,antipyretic drugs that leads to the cardiac problems.Drug like morphine has been treated for chronic cancer pain which encourages the spread of cancer cells in the patient's body.Therefore,the addiction to the pain killers should always be avoided wthout doctor's supervision.We should always treat them
as one of the pain treatment plan.