Trihexyphenidyl abuse (Parkinol, the 'cockroach pills'): harms and treatment

What are cockroach pills? The short answer

Cockroach pills (in Egypt 'hobob el-sarasir' or 'barsham el-sarasir', sometimes 'the cockroach drug') is a street name for the medicine Parkinol, whose scientific name is trihexyphenidyl. It is not a drug made in secret, but a real medicine: the US National Library of Medicine's MedlinePlus explains that it is used along with other medicines to treat the symptoms of Parkinson's disease, and to control movement symptoms such as tremor and slurred speech caused by certain medicines. Trihexyphenidyl abuse is what happens when this useful medicine is taken in ways no doctor prescribed.

The trouble starts when it is taken without a prescription, in a larger amount than prescribed, or with other substances to get a 'buzz'. At that point a helpful medicine becomes a real danger to the mind, the heart and body temperature. The same substance has other names in different Arab countries, such as Artane, the name it goes by in Iraq and Syria, and some people call it Parkizol. The names differ, but it is the same substance with the same risks.

If you have found this medicine with a relative, this article will help you understand what is going on and what to do next, without panic and without playing it down.

Why is a Parkinson's medicine misused?

Parkinol belongs to the anticholinergic medicines, which work against acetylcholine, a chemical messenger in the body and brain. A systematic review published in the journal Biomedicines in 2022, which gathered the published studies on anticholinergic drug abuse and misuse, found that trihexyphenidyl was the one that appeared most often in the research. Reasons for misuse mentioned in the review include:

• Seeking a high, relaxation or extra energy.
• Using it together with other substances such as sedatives, alcohol or opioids. The review notes that these other substances make the body's reactions unpredictable.
• Some patients taking more than they were prescribed, sometimes to counter side effects of their psychiatric medicines or to feel a lift in mood.
• Easy access, because it is a prescribed medicine in the first place: much of what is misused comes from genuine prescriptions.

The medicine's own official prescribing information warns that indiscriminate use to keep up a continued high can lead to psychiatric disturbances. The review notes that most of the people whose cases were described were young men, many of them psychiatric patients taking antipsychotic medicines. It also stresses that the available evidence is limited and mostly based on case reports, and it gives no figures on how common the problem is in Egypt or the Arab world.

Where does the name 'cockroach pills' come from, and how dangerous are the hallucinations?

People commonly say the street name comes from the frightening visual hallucinations described by those who have misused the medicine, such as seeing insects or moving things that are not there. This is a popular story, not a medical term. What is scientifically established is that hallucinations and confusion are known harms: MedlinePlus lists confusion, delusions and hallucinations among the serious side effects that mean you should contact a doctor immediately.

What harms does trihexyphenidyl abuse cause?

The 2022 systematic review describes a group of symptoms known as anticholinergic poisoning (anticholinergic toxicity). The main harms can be summed up as follows:

• Overheating: these medicines reduce the body's ability to sweat. The MSD Manual notes that heatstroke can occur after taking anticholinergic medicines, and the risk is higher with physical effort and in hot weather.
• Strain on the heart: a fast or irregular heartbeat and high blood pressure, and in severe poisoning, dangerous heart rhythm problems.
• Confusion, forgetfulness and poor concentration: muddled thinking, losing track of place and time, and difficulty paying attention and remembering.
• Delirium (an acute disturbance of awareness): agitation, hallucinations, suspicion and persecutory thoughts, and in severe poisoning it can even lead to coma.
• Other physical symptoms: dry mouth, wide pupils and blurred vision, difficulty passing urine, constipation, and flushed, hot skin.

Older people are more sensitive

The official prescribing information listed by the US National Library of Medicine (DailyMed) warns that older people, particularly those over 60, often become more sensitive to medicines of this type and need careful adjustment by their doctor. MedlinePlus says older adults should not usually take it, because it is not as safe or effective as other medicines that treat the same condition. The MSD Manual lists anticholinergic medicines among the most common causes of delirium (sudden confusion and disturbed attention), and notes that older people are more sensitive to them. A large study in England, published in JAMA Internal Medicine in 2019, also found a link between long-term use of strong anticholinergic medicines, including Parkinson's medicines, and a higher risk of dementia in people aged 55 and over. The researchers stressed that the study shows an association and does not prove that the medicine is the cause.

Is Parkinol addictive? And what about people who take it on prescription?

Yes, Parkinol can cause dependence and addiction when it is misused. The 2022 systematic review reports tolerance (needing more to get the same effect) and withdrawal symptoms with chronic use, as well as psychological dependence with strong cravings. In a survey of 100 psychiatrists in Tunisia, published as an abstract in European Psychiatry in 2015, 87% said this medicine has the potential to cause dependence.

But it is important not to confuse two different things: many people with psychiatric conditions take it on a sound prescription to treat tremor, slurred speech and other movement symptoms that some antipsychotic medicines can cause. It is not right to call them addicted; the medicine is part of their treatment. That is why the doctor handles the matter calmly:

• Checking whether the medicine is still truly needed, or whether the main psychiatric medicine can be adjusted so the side effects ease.
• Watching for signs of misuse, such as repeatedly asking for a higher amount or going from doctor to doctor to get prescriptions, signs the systematic review describes.
• Deciding on a gradual reduction or a switch to an alternative, depending on each patient's situation.

If your relative takes it on prescription, do not stop it yourself or change the amount; talk to their doctor. If they have a psychiatric condition together with misuse, this is known as dual diagnosis, and it needs treatment that covers both sides together.

Trihexyphenidyl misuse symptoms: signs a family may notice

No single sign is enough to judge, because some of them can have other causes, and a diagnosis is made by a doctor. But several signs together deserve attention:

• Disconnected speech, talking to people who are not there, or sudden fear of things you cannot see.
• Confusion, forgetfulness and difficulty concentrating that are not like them.
• A flushed face, hot skin, a dry mouth and wide pupils.
• A pounding heart, or complaints that their heart is racing.
• Changes in sleep, mood and temper, and pulling away from family and friends.
• Prescribed medicine running out before it should, medicines found without a prescription, or money going missing.

Why must Parkinol never be stopped suddenly?

MedlinePlus warns against stopping this medicine suddenly without talking to a doctor, because sudden stopping can bring back the symptoms it was prescribed for. With chronic use, the 2022 systematic review describes withdrawal symptoms such as anxiety, insomnia, restlessness, sweating, irritability, headache and a racing heart. Things become more complicated if the person is also using other substances, or has a psychiatric condition whose treatment needs follow-up at the same time.

Parkinol addiction treatment: how assessment and treatment work

Treatment does not start with medicine alone, but with understanding the whole picture. It usually goes through these steps:

1. Appointment and first assessment: the doctor asks about the substances used and for how long, about prescribed medicines and physical illnesses, and a drug test is done to see whether other substances are involved.
2. A full psychiatric assessment: because many people who misuse this medicine have a psychiatric condition, the doctor needs to know the underlying diagnosis and set the right psychiatric treatment.
3. Withdrawal under medical supervision: the doctor decides how to reduce the medicine and which supporting medicines to use, depending on the case, while monitoring the heart, body temperature and mental state. This can take place in the detox unit when needed.
4. Rehabilitation and relapse prevention: therapy sessions and behavior modification, work with the family, and follow-up after discharge.

At Oxygen Center in Damanhour, you can start with an outpatient doctor's appointment, for men and women. Inpatient stays for detox or inpatient psychiatric treatment are for males aged 15 and over (under 18 with a guardian's consent), and the center does not provide services for children under 15.

What should the family do first, and when should you get help?

1. Calm down before you talk: shouting and accusations push the person into denial and hiding. Choose a time when they are calm and not under the influence.
2. Talk about your worry, not their faults: 'I'm worried about you because I've noticed this' works far better than accusations or labels.
3. Do not stop their prescribed medicine yourself: if they take it on prescription, get in touch with their doctor.
4. Book an appointment soon: if the person refuses to come, the family can come alone first to understand the options.
5. Support without funding the problem: learn how to support someone without enabling addiction.

Get specialist help if they keep using it without a prescription, if hallucinations or confusion appear even once, if they mix it with other substances, or if they have tried to stop and could not. You can contact Oxygen Center by call or WhatsApp on +20 101 687 0711, on the landline +20 45 320 0011, or on the 24/7 emergencies and complaints line +20 100 006 6752. In Egypt, the hotline of the Fund for Drug Control and Treatment of Addiction, 16023, offers confidential treatment through its partner centers.

If your relative talks about death or about harming themselves, take it seriously: ask them directly and calmly what they are thinking, and listen without blame. If they are in immediate danger, have harmed themselves or you fear they are about to, do not leave them alone: call the ambulance on 123 straight away (or your local emergency number), or take them to the nearest emergency department. If the danger is not immediate, you can call the Ministry of Health's mental-health hotline on 16328 or Oxygen Center's emergency line on +20 100 006 6752, both available 24/7, for advice and support. These crises can be overcome with the right help.