pharma sheet # 23 - Noor haddadin

Handout # 12
Sheet # 23
Date of lec:8.11.2010



-In this lecture we will continue talking about opioid analgesics .

-One of the opioids is the morphine : mimic the endorphin and enkephalin within our bodies in the postsynaptic area, as it synapses with the opiod receptors on the postsynaptic neurons (see slide # 4) this binding:
1)decreases the excitability of the neuron.
2) Increases the k+ entrance .
3)decreases Ca+2 influx .

-So the end result is the reduction of the conductivity and the action potential.
-This is the mechanism of the opioids in providing analgesia also they can be used in post operation due to its hypnotic effect.(tanweem)

-Also we can use opioids derivativesin moderate to severe pain .
(severe pain :sustained responding pain toward NSAID)


-When pain starts we usually give acetaminophen coz its safe and easy to use for moderate or mild pain, if it wasn’t sufficient we move toward NSAID, but if more analgesia is required either we use opioids +NSAID or acetaminophen + opioids. Here we have to pay attention that the patient doesn’t have renal or heart problems, and that he doesn’t have contraindication toward the NSAID.

-Giving opioids + NSAID increase the efficacy toward the analgesia (either additive or synergic activity).

-Remember :not all patients can take opioids
Never give patients opioids unless they are in a real need to them.


-Why we don’t give opioids from the beginning of any pain?
Because it causes addiction.


-Opioids analgesics indications: (slide # 3)

1)cough centre suppression
Coldex is a drug used for cough,it also causes euphoria.

2)treatment of diarrhea:opioids can treat diarrhea but that’s very very rare.

3)balanced anaesthesia :has interaction with dentistry but also rare.
Sometimes dentists do general anaesthesia and after that they give opioids .ex:morphine is given to relax patients.


*The table (slide #7):

*Codeine :
-partial agonists
-the fisrt choice to use in dentistry
-safest to use
-less efficacious than morphine (cant be that effective in severe pain and doesn’t cause too much addiction ,also has a lower potency than morphine )
-very good for analgesia
-6o mg is used in each dose
-is used to mild-moderate pain
-is also used for cough


-note that codeine is the 1st choice between opioids to use in dentistry but we should have tried the NSAID first with the patient ,if NSAID didn’t relief the pain we use codeine.


-Why we shouldn’t increase the codeine concentration more than 60 mg?
Because we have ceiling effect here;that means 60 mg is enough to give Emax ,increasing the dose more than 60 mg wont be effective coz we already reached the Emax for the drug. Increasing the dose here more than 60 mg will only increase the side effects , the toxicity and the respiratory depression.

*hydrocodeine (oxycodone):

-2nd choice to use in dentistry
-more potent than codeine (10 mg only)
-less potency than methadone and morphine and fentanyl



*Morphine:

-has a good activity toward the pulmonary edema (relief pain and dilates the vessels around the heart )
-it’s the only opioid used in pulmonary edema case
(pulmonary edema is caused by congestive heart failure)
-taking morphine orally is not effective coz it has a very bad first dose effect in the liver ,so its given by injections.
-it’s the drug of choice for cancer patients to relief severe pain.



*Remember that the emergency kit should contain:
1)morphine
2)atropine
3)adrenaline

*Fentanyl:
-advantages :doesn’t cause euphoria as morphine
-stronger than morphine (potent 100 time than morphine)
-is used in epidural during delivery


*Meperdine:
-stronger agonist with anticolinergic effect (causes xerostima)
-is the 3rd choice to use in dentistry


-Slide # 8 (the dr only read it)
Diaphoresis :profuse sweating or perspiring (calm skin)
The body can get tolerant to all of these side effects except the pupil constriction which is the most common side effect that detect if the person is addict or not.

-Slide # 9:
-Tolerance leads to addiction
-Tolerace :physiologic phenomenon resulting in progressive decline in potency of an opioid with continued use.
(desensitization for the receptors either by decreasing their # or by decrease coupling between the drug and receptor ,therefore the patient need to increase the dose to obtain the wanted effect).

-Dependence :physiologic state characterized by withdrawal symptoms uron abrupt discontinuation (reduction)of nacrotic therapy.
That means when u inhibit the drug from the patient after he got used to it (the inhibitory activity of the opioid is no longer present in the body, as a result withdrawal signs appear which are the opposite signs of the morphine activity)

Withdrawal signs # acute analgesia
So for example here instead of respiratory inbibition he starts to hyperventilate.


-The dr read slide # 11: gooseflesh :cold hands.

-morphine addiction is not lethal.


-Slide # 12:
-codeine dental comment:
it is recommended that codeine not to be used as the sole entity for analgesia because of moderate efficacy along with relatively high incidence of nausea, sedation ,and constipation. That means 60 mg is insufficient to relief pain ,but giving it with paracetamol for example will increase the efficacy ,so don’t use it alone

-Sodium thiosulfate is the chemical used against codeine poisoning (antidote).

-Antidote for morphine and heroin is naloxone .

-The dr read slides 13+14+15.

-Note:narcotic drugs are opioids.







Done by : Noor Haddadin

Good luck