How morphine works
Morphine is a drug from the opiate group. It has a strong analgesic (pain-relieving), cough-relieving (antitussive) and sedative or depressant effect.
Humans have an endogenous analgesic system that is activated in stressful situations, among other things. For example, it is often possible for injured people to initially help others after serious accidents without even noticing their own injury.
This analgesic system can also be activated by the active ingredient morphine. The drug binds to certain messenger substance docking sites in the central nervous system (opioid receptors), which impedes the transmission of pain and reduces the sensation of pain. It also leads to sedation, which supports the analgesic effect of morphine.
Absorption, breakdown and excretion
The active substance is only absorbed slowly and incompletely from the intestine into the blood after being taken by mouth (perorally). After distribution in the body, it is broken down in the liver. This produces degradation products that still have an analgesic effect. They are then mainly excreted via the kidneys.
When is morphine used?
Morphine is used to treat severe and very severe pain, for example in cancer patients.
How morphine is used
Normally, the dosage for adults is between 60 and 120 milligrams per day. However, if the active ingredient is injected directly into the blood, the dose is lower (usually between 10 and 60 milligrams).
The painkiller only has a relatively short duration of action of two to four hours. For this reason, delayed-release tablets are often given. They enable a constant release of the active ingredient and therefore long-lasting pain relief. The effect of these prolonged-release tablets only sets in after around three hours, but then lasts for almost a whole day. However, if an immediate effect is desired, other forms of administration are used – for example morphine drops.
Medication with morphine should always be discontinued “gradually”, i.e. not abruptly, but by gradually reducing the dosage. This helps to avoid acute withdrawal symptoms.
What side effects does morphine have?
Morphine frequently (i.e. in one to ten percent of those treated) causes side effects such as headaches, euphoria, tiredness, mental disorders, nausea, constipation and sweating.
Very rarely (i.e. in less than one percent of those treated), there is a drop in blood pressure, breathing difficulties and allergic reactions.
What should I bear in mind when taking morphine?
Contraindications
Medication containing morphine must not be taken in the following cases
- Intestinal obstruction
- Respiratory problems including impairment of mucus secretion in the airways
- obstructive respiratory diseases (diseases with narrowing of the airways)
- seizures
- Acute abdomen (summary of life-threatening diseases of the abdominal cavity)
- Simultaneous intake of antidepressants from the group of monoamine oxidase inhibitors (MAO inhibitors)
Interactions
If the painkiller is taken together with other medications, interactions may occur. The following drugs can increase the effects and side effects of morphine:
- Alcohol and central depressant substances (e.g. benzodiazepines)
- Drugs for depression and mental illness (e.g. clomipramine, amitriptyline)
- Anti-nausea agents (such as diphenhydramine)
- Cimetidine (remedy for heartburn)
The antibiotic rifampicin can weaken the analgesic effect of morphine.
Ability to drive and operate machinery
Taking morphine can impair your ability to react. Therefore, especially at the beginning of treatment, you must not actively participate in road traffic or operate heavy machinery.
Age restrictions
Pregnancy and breastfeeding
Because morphine also reaches the unborn child via the mother’s blood, pregnant women with severe pain should only be given the painkiller after a strict risk-benefit assessment. This applies in particular to use shortly before birth, as morphine can cause breathing difficulties and adaptation disorders in the newborn.
Morphine passes into breast milk in significant quantities. To date, however, no serious side effects have been reported in breastfed children when the mother received the painkiller. Short-term use during breastfeeding is therefore possible.
How to obtain medication with morphine
Morphine is subject to the Narcotics Act in Germany and Switzerland and the Narcotic Drugs Act in Austria. The active ingredient is therefore only available in pharmacies with a special prescription (narcotic or addictive drug prescription).
How long has morphine been known?
Morphine has been known as a natural component of opium for a very long time. The substance was first isolated at the beginning of the 19th century. Even then, people were aware of its anaesthetic and euphoric effect, but also of the danger of succumbing to a life-threatening respiratory arrest in the event of an overdose.
What else you should know about morphine
However, if morphine is misused, the pain-induced activation of the respiratory regulation center is absent and respiratory distress or even respiratory arrest can occur.