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Morphine: characteristics and effects in the short and long term

Morphine: characteristics and effects in the short and long term

April 26, 2024

Whether it has been administered to us by a general culture or because we have read or seen it on some occasion, most of the population knows what morphine is. This substance derived from opiates It produces a deep anesthesia at the same time that it usually generates pleasurable sensations. However, most people usually have a vague and general idea of ​​its effects.

In this article they are going to present the effects of morphine, both short and long term .

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Morphine as a psychoactive substance

Morphine is a psychoactive substance derived from the opium plant or opium poppy . This drug is like the rest of the opium derivatives a powerful depressant agent of the nervous system, forming part of the group of psycholeptic substances.


In this way, morphine has effects that mainly they are associated with decreased brain activity and that cause a powerful relaxing, analgesic and narcotic effect. In fact its own name evokes these effects, since it comes from the Greek figure of Morpheus.

In addition, apart from this narcotic effect it also causes pleasurable sensations, such as the feeling of being floating and a certain euphoria .

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Its use

The use of morphine It is very widespread at the medical level as an anesthetic and analgesic when it comes to fighting the pain of some surgeries or diseases such as cancer.


It has also been used occasionally to treat addiction and withdrawal syndrome to heroin, a drug derived from morphine. However, there is a risk of acquire dependency and addiction to this substance, so its use must be very regulated.

On the other hand, in some cases it has come to be used recreationally. Consumption is usually through an intravenous line , although there are presentations in the form of ingestible tablets.

You have to bear in mind that your consumption can generate powerful side effects that can even endanger the life of the subjects if the dose is not adequately controlled.

Mechanism of action

Morphine, like most opiate derivatives, has its action in the body due to its interaction with the endogenous opioid receptors present in our organism, of which it is agonist.


In the same way it causes an effect in the synthesis and transmission of noradrenaline, producing a lower transmission of this substance.

Effects of morphine in the short term

The short-term effects of morphine are many and varied, being generally the reason why they are applied both at a medical level and in other situations. However, side effects or harmful effects can also be generated if the dose is excessive. Some of them are the following.

1. Analgesia

Morphine It is one of the most powerful analgesics that are known , causing the absence of pain perception in most cases. The pain caused by cancers, injuries, heart attacks or surgeries can be treated medically with morphine or some derivative of it.

2. Sedation

Another of the main effects of morphine is sedation, which can range from mild relaxation to drowsiness excessive and prolonged. In fact, such is its power in this sense that excessive administration could cause the patient's coma.

3. Initial euphoria

Opium derivatives, such as morphine, initially generate a high level of euphoria and later cause sensations of relaxation and drowsiness.

4. Gastrointestinal and digestive tract disorders

It is not strange that people who consume morphine have gastrointestinal discomfort, as well as constipation, dry mouth, nausea and vomiting .

5. Effects on the muscles: feeling of heaviness, heat or stiffness

It is common for one of the effects of morphine to be the sensation of heaviness in the muscles of the extremities. But nevertheless when the doses are high , morphine can cause high rigidity in the abdominal and thoracic muscles, as well as in other muscle groups.

6. Effects on the respiratory system

As we have said, morphine causes a depression of the nervous system which generates the analgesia and sedation described above. One of the nuclei that reduces its activity is that linked to respiration, which it becomes slower and shallower .

It can also cause a depression of cardiorespiratory function that can lead to the death of the consumer if the dose used is not controlled.

7. Reduce blood pressure

Another effect of morphine occurs at the level of blood pressure, which reduces by reducing the performance of the autonomic nervous system. As well can cause bradycardia or arrhythmias .

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8. Pupillary miosis

As with heroin, morphine usually causes alterations such as miosis or contraction of the pupils.

9. Hallucinations

Sometimes the consumption of morphine produces the perception of elements that do not find a correlate in the real world.

However, outside of hospital contexts in which the dose is being controlled this effect usually indicates the presence of serious poisoning .

10. Seizures

Sometimes, and especially in case of overdose, they can be generated reactions in the form of agitation, tremor and even convulsions uncontrolled

Long-term effects

Generally the use of morphine occurs in specific and controlled contexts in which a large number of doses are not used, or is used as a palliative element in terminal patients. In these cases, the existence of serious long-term effects is not usually considered.

However, sometimes the consumption of morphine has to be prolonged for some time, or the user uses it frequently, regardless of the professional indications. In these cases, in addition to the possible short-term effects, those that have accumulated consumption over time should be added, being the main risk the acquisition of tolerance and dependence to the substance. In this aspect we can consider the following effects.

1. Dependence

One of the possible effects of morphine in the long term if there is a more or less frequent consumption, as with the rest of opiates, is the acquisition of dependence towards it. Morphine is a substance with a high addictive potential , like heroin, which can cause serious consequences both mental and behavioral.

2. Cognitive and impulse control effects

One of the long-term effects of morphine in those cases in which prolonged and continuous use is made and dependence occurs is to cause alterations such as Decreased judgment, dysphoria and decreased impulse control .

3. Severe constipation

One of the effects of morphine is the presence of intestinal discomfort and difficulties in excretion. In the long term, severe constipation can occur for the habitual consumer.

4. Social problems and risk behaviors

The dependence and abstinence of this substance or other types of opiates can generate impulsive and antisocial behaviors, which can come from the disconnection and loss of relationships even the commission of robberies or even blood crimes in order to obtain resources to get a dose.

Risk behaviors can also be carried out the sharing of syringes among dependent people, which can cause the spread of diseases such as HIV and hepatitis.

5. Withdrawal syndrome

The cessation of consumption in dependent consumers, if carried out abruptly, can generate serious effects on health. At the physiological level it usually produces dysphoria or emotional distress, anxiety, craving or desire for consumption, vomiting and diarrhea, pain, mydriasis or pupillary dilation, insomnia, fever and even convulsions.

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Alterations in pregnant and lactating

Morphine can be transmitted through blood or breast milk, so it should not be used in pregnant or lactating women. It can generate dependence on the offspring, which in addition to the possible short-term effects can have serious repercussions for the development of the baby .

Bibliographic references:

  • Santos, J.L. ; García, L.I. ; Calderón, M.A. ; Sanz, L.J .; de los Ríos, P .; Left, S .; Román, P .; Hernangómez, L .; Navas, E .; Thief, A and Álvarez-Cienfuegos, L. (2012). Clinical psychology. CEDE Preparation Manual PIR, 02. CEDE. Madrid.

9 Signs Someone You Love is Addicted to Opioids (Pain Medications) (April 2024).


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