• Any drug that relieves pain selectively without blocking the conduction of
nerve impulses or effecting the consciousness.
• This selectivity is an important distinction between an analgesic and
• For example in the condition of muscle aches and headache we use
analgesics where there is no possibility of becoming addicted.
• And these can be used to get relieve pain after surgery, injury such as after
• For acute pain such as twisted ankle etc.
• Analgesics are divided into two groups,
• Opioids(which predominantly influence the central nervous system CNS).
• Non opioids(which act predominantly on peripheral nervous system PNS)
. Paracetamol is an antipyretic as well as analgesic .its action is mainly in
central nervous system. It is useful for mild pain.
Paracetamol is commonly called as panadol.
It does not contain anti inflammatory properties.
• NSAIDs act predominantly at peripheral nervous system by interfering to
the chemicals that sensitize the nerve endings to pain. They have anti
inflammatory, anti pyretic and analgesic properties. These drugs include
ibuprofen and diclofenac.
• They are effective for mild to moderate pain.
9. How to take analgesics?
• Pain relievers are available in many forms, including:
• Films you place under the tongue to dissolve.
• Liquid you inject into your body with a syringe.
• Liquid you swallow
• Nasal spray that goes to nose.
• Patches ,pastes etc.
10. Pain medication
• Over time ,you may that an analgesic can become less and less effective
which is called tolerance.
• in this case you need higher doses or more frequent doses, but you should
be careful to avoid side effects and dependence.
13. OPIOID ANALGESIC
• Narcotics/ morphine like analgesics are included in this category. The opioid
Analgesic were once called narcotic drugs they act on the brain and can
induce sleep. The opioid Analgesics can be used for either short term or
long term relief of severe pain.
14. SUBCLASSES OF OPIOID
• Further divided into three subclasses which are;
• Natural opium alkaloids
• Codeine ( most commonly use strong analgesic ,less addictive than morphine, similar
to morphine except for the replacement of a OH group with OCH3 group)
16. NON OPIOID ANALGESICS
• NSAIDS (non-steroidal anti inflammatory drugs)/ non narcotics/aspirin like
• Non opioid analgesics which alleviate pain by reducing local inflammatory
response. In contrast, the anti-inflammatory compounds are used for short-
term pain relief and for modest pain, such as that of headache, muscle strain,
bruising, or arthritis.
17. NON OPIOID (ANTI-INFLAMMATORY
• Most anti-inflammatory analgesics are derived from three compounds discovered in
the 19th century.
• Salicylic Acid
• Phenacetin (or acetophenetidin)
• Although chemically unrelated, the drugs in these families have the ability to relieve
mild to moderate pain through actions that reduce inflammation at its source.
18. SALICYLIC ACID
• Salicylic acid has the formula C7H6O3.
• It is colorless crystalline organic acid.
• Salicylic acid as a medication is used most commonly to help remove the outer layer
of the skin. AS such, it is used to treat warts(warts are typically small, rough, and
growths that are similar in color to the rest of the skin) psoriasis (psoriasis is a long-
lasting autoimmune disease characterized by patches of abnormal skin. These skin
patches are typically red, itchy and scaly),dandruff, acne, ringworm
(Dermatophytosis,also known as ringworm, is a fungal Infection of the skin).
• The drugs of these families have the ability to relieve mild to moderate pain
through actions that reduce inflammation at its source.
• Phenacetin (or acetophenetidin) is a pain relieving and fever reducing drug,
which was widely used between its introduction in 1887 and the 1983 has
imposed by the U.S. food and drug administration.
22. SALICYLIC ACID DERIVATIVE
• Acetylsalicylic acid , or aspirin, which is derived from salicylic acid,is the most
widely used mild analgesic. It is considered the prototype for anti-
23. PHENACETIN DERIVATIVE
• Acetaminophen (a derivative of phenacetin) and the aspirin like drugs, or
Nonsteroidal anti-inflammatory drugs (NSAIDs),which include compounds
such as ibuprofen, naproxen and fenoprofen.
24. PYRAZOLONE DERIVATIVE
• Pyrazolone derivatives, with some exceptions, are no longer widely used in
many countries, because of their tendency to cause acute infection know as
agranulocytosis (Agranulocytosis, also known as agranulosia is an acute
condition involving a severe and dangerous leukopenia (lower white blood
cell count) ,most commonly of neutrophils causing a neutropenia in the
circulating blood. It is a severe lack of one major class of infection-fighting
white blood cells)
26. Mechanism of analgesics
• Aspirin and NSAIDs appear to share a similar molecular
mechanism of action—namely, inhibition of the synthesis
of prostaglandins (natural products of inflamed white blood cells)
that induce the responses in local tissue that include pain and
• In fact, aspirin and all aspirin-like analgesics, including
indomethacin and sulindac, which are derived from a
heterocyclic organic compound known
as indole, inhibit prostaglandin synthesis and release.
• All these agents can be further divided into nonselective COX
inhibitors and selective COX inhibitors. COX, or cyclooxygenase, is
an enzyme responsible for the synthesis of prostaglandins and
• It has two forms, COX-1, which is found in most normal tissues,
and COX-2, which is induced in the presence of inflammation.
• Because COX-2 is not normally expressed in the stomach, the use of
COX-2 inhibitors (e.g., rofecoxib, celecoxib) seems to result in less
gastric ulceration than occurs with other anti-inflammatory
analgesics, particularly aspirin.
• However, COX-2 inhibitors do not reduce the ability of platelets to
form clots, a benefit associated with aspirin and other nonselective
• Preferences in COX selectivity and the possibility of additional
molecular actions of NSAIDs may explain differences in the
therapeutic effects between aspirin, acetaminophen, and NSAIDs.
• For example, while aspirin is effective in reducing fever, as well as
relieving inflammation, acetaminophen and NSAIDs are more
potent antipyretic (fever-reducing) analgesics.
• Acetaminophen, on the other hand, possesses inferior anti-
inflammatory activity compared with aspirin and NSAIDs and thus
is relatively ineffective in treating inflammatory conditions such
as rheumatoid arthritis.
• Despite this, acetaminophen is a popular mild analgesic and
antipyretic and is a suitable alternative to aspirin for patients who
develop severe symptoms of stomach irritation, because it is not as
harmful to the gastrointestinal tract.
36. TRANSDERMAL ROUTE
• Definition: opioids administered by a transdermal route are absorbed into
vessels located in subcutaneous tissue and, subsequently, are conveyed in the
blood to opioid receptors localized in the central nervous system (CNS).
37. TOPICAL ROUTE OF ANALGESICS
Definition: Non–steroidal anti–inflammatory drugs (NSAIDs) applied
topically are absorbed into systemic circulation in a limited percentage, and the
main mechanism of action is based on a high concentration in the structures of
joints and the provision of local anti–inflammatory effects.
EXAMPLE: Lidocaine and capsaicin in patches, capsaicin in cream, EMLA
cream, and creams containing antidepressants (e.g., doxepin)act mainly locally
in tissues through receptors and/or ion channels.
• Transdermal and topical routes of opioid administration are also associated
with a lower risk of addiction compared to oral and parenteral routes of
opioid analgesics administration.
40. BENEFITS OF TRANSDERMAL
The use of the transdermal route allows for the avoidance of problems associated with a
disturbed absorption of a drug from the gastrointestinal (GI) tract or other GI problems (i.e.,
swallowing difficulties, nausea, vomiting)
as well as the elimination of the first pass effect through the liver.
Low concentrations of drugs and small fluctuations of their concentration in the blood serum
guarantee long–lasting analgesia with a lower number of adverse effects, especially nausea,
vomiting, and constipation.
The transdermal form of drugs provides simplicity and convenience of administration, and
improves patients’ quality of life.
a transdermal route, which offers non–invasive and convenient route of analgesics administration
that is especially indicated for patients with stable pain syndromes and those with GI tract
• The first drug used in the treatment of pain through the transdermal route
• Patches of fentanyl release 12.5, 25, 50, 75, and 100 µg/h.
42. BENEFITS OF TOPICAL ROUTE
• Clinical studies have demonstrated analgesic efficacy when opioids are
applied topically in certain situations such as skin ulcers .
• The advantage of administering an opioid topically is the avoidance of
systemic adverse effects such as nausea, constipation.
• much better profile for adverse effects because they are designed for local
pain treatment with minimal systemic effects. This refers especially to those
groups of drugs in which systemic absorption is negligible.
43. DURATION OF TOPICAL DRUGS
• The duration of action of topical morphine has been reported to be as long
as 7–12 h, which is longer compared to morphine administered by oral or
parenteral routes (4–6 h). There are ongoing studies on the use of morphine
administered systemically in transdermal patches.
44. Benefits of analgesics:
• Relief of physical pain.
• Relief of the emotional and psychological pain.
• Induce a state of euphoria.
• Reduced coughing reflex
• Reduce tension, worry and fear.
45. Side effects of analgesis:
• Major effects on the central nervous system.
• Effect on gastrointestinal activity:
Opoids analgesis inhibit relaxation of
the lower esophageal sphincter, decrease propulsion of smooth muscles in the
small and large intestine, increase pyloric and anal sphincter tonus, delay gastric
46. Cardiovascular side effects:
• Analgesics reduce heart rate.
• Analgesics cause heartburn.
• Analgesics cause cardiac arrest.
• It also causes abnormal heart beats.
• Damage to internal organs, such as the liver or kidneys.
• Diarrhea or constipation
• Ringing in the ears, or even deafness.
• Stomach ulcers
• Hypersensitivity response
• Trouble forming clots in the blood, which can lead to excessive bleeding.
• Unusual weeight gain
• Yellowish skin or eyes
• Muscular rigidity and contractions
• Risk of dangerous infections like hepatitis or AIDS due to shared needeles.
• Produces dowsiness
• Causes sedation
• What makes opioid medications effective for treating pain can also make
them dangerous. At lower doses, opioids may make you feel sleepy, but
higher doses can slow your breathing and heart rate, which can lead to death.
And the feeling of the pleasure that result frim taking opioid can make you
want to continue experiences those feelings whichead to addiction.