Donnatal 16.2mg Tablets

Donnatal combines the anticholinergic effects of hyoscyamine, atropine, and scopolamine with the sedative effects of phenobarbital. The anticholinergics act by competitively blocking the action of acetylcholine at muscarinic receptors, leading to relaxation of smooth muscle (e.g., gastrointestinal tract), reduction of glandular secretions, and effects on the heart and eyes. Phenobarbital is a barbiturate that produces non-selective CNS depression, ranging from mild sedation to hypnosis and coma, by binding to GABA-A receptors and enhancing the inhibitory effects of GABA, primarily by increasing the duration of chloride channel opening.

Serious Side Effects: Seek Medical Help Immediately

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention right away:

Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Trouble sleeping
Diarrhea
Severe constipation or stomach pain, which may indicate a severe bowel problem
Inability to sweat during physical activity or in warm temperatures
Muscle pain or cramping
Fast or abnormal heartbeat
Difficulty passing urine
Changes in eyesight, eye pain, or severe eye irritation
Erectile dysfunction
A severe skin reaction, known as Stevens-Johnson syndrome or toxic epidermal necrolysis, which can cause severe health problems and potentially be life-threatening. Seek medical help immediately if you experience:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes

Other Possible Side Effects

Like all medications, this drug can cause side effects. Many people may not experience any side effects or may only have mild ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical attention if they bother you or do not go away:

Dizziness
Drowsiness
Fatigue
Weakness
Blurred vision
Headache
Constipation
Bloating
Dry mouth
Upset stomach or vomiting
Feeling nervous and excitable
* Changes in taste

This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
Certain health conditions, including:
+ Heart problems caused by bleeding
+ Bowel blockage
+ Enlarged colon
+ Glaucoma
+ Hiatal hernia (a hernia that involves your stomach)
+ Myasthenia gravis
+ Slow-moving gastrointestinal (GI) tract
+ Urinary retention or difficulty passing urine
+ Ulcerative colitis
A history of porphyria, a rare genetic disorder
Previous experiences of restlessness or overexcitement after taking phenobarbital
* Past or current struggles with alcohol or drug use disorder

This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist. They will help determine if it is safe to take this medication with your existing health conditions and other drugs. Never start, stop, or adjust the dosage of any medication without consulting your doctor first.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Long-term use of this drug may lead to dependence. If you have been taking this medication for an extended period, consult your doctor before stopping, as you may need to gradually taper off the dosage to avoid potential withdrawal effects.

Until you are familiar with how this medication affects you, exercise caution when driving or performing tasks that require alertness and clear vision. Additionally, consult your doctor before consuming alcohol, using marijuana or other cannabis products, or taking prescription or over-the-counter medications that may impair your reactions.

In hot weather or during physical activity, be mindful of your fluid intake to prevent dehydration. Drink plenty of fluids to avoid fluid loss. If you are allergic to tartrazine (FD&C Yellow No. 5), discuss this with your doctor, as some formulations of this medication may contain this ingredient.

If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Women taking birth control pills or other hormone-based contraceptives should be aware that this medication may reduce their effectiveness. To prevent pregnancy, consider using an additional form of birth control, such as a condom, while taking this medication.

If you are pregnant or become pregnant while taking this medication, contact your doctor immediately, as it may pose a risk to the unborn baby. Breastfeeding mothers should consult their doctor to discuss potential risks to their infant.

• Potassium chloride (solid dosage forms) - increased risk of GI lesions due to delayed transit.
• Other anticholinergics (e.g., tricyclic antidepressants, antihistamines, phenothiazines, quinidine, disopyramide) - additive anticholinergic effects.
• CNS depressants (e.g., alcohol, opioids, benzodiazepines, other sedatives) - additive CNS depression.
• MAO inhibitors - may prolong and intensify the effects of phenobarbital.
• Valproic acid - may increase phenobarbital levels.

• Oral anticoagulants (e.g., warfarin) - phenobarbital can decrease anticoagulant effect via CYP induction.
• Corticosteroids - phenobarbital can decrease corticosteroid effect via CYP induction.
• Doxycycline - phenobarbital can decrease doxycycline levels via CYP induction.
• Oral contraceptives - phenobarbital can decrease efficacy via CYP induction.
• Griseofulvin - phenobarbital can decrease griseofulvin levels via CYP induction.
• Phenytoin - complex interaction, phenobarbital can increase or decrease phenytoin levels.
• Digoxin - anticholinergics may increase digoxin absorption, phenobarbital may decrease digoxin levels.
• Metoclopramide - antagonistic effects on GI motility.

• Antacids - may decrease absorption of anticholinergics if given concurrently.
• Ketoconazole, Itraconazole - phenobarbital can decrease antifungal levels.
• Beta-blockers (e.g., propranolol) - phenobarbital can decrease beta-blocker levels.
• Calcium channel blockers (e.g., verapamil, nifedipine) - phenobarbital can decrease CCB levels.
• Levodopa - anticholinergics may decrease levodopa absorption.
• Thyroid hormones - phenobarbital can increase metabolism of thyroid hormones.

• Gastrointestinal motility agents (prokinetics) - antagonistic effects.
• Topical anticholinergics - additive systemic effects.

• Dry mouth
• Blurred vision
• Constipation
• Urinary retention
• Dizziness
• Drowsiness/Sedation
• Nausea/Vomiting
• Nervousness
• Headache
• Palpitations
• Confusion (especially in elderly)
• Rash

Donnatal is Pregnancy Category D due to the phenobarbital component. Barbiturates can cause fetal harm, including congenital malformations (e.g., cleft lip/palate, cardiac defects) and neonatal withdrawal symptoms (e.g., irritability, tremors, hypertonia, feeding difficulties) if used during pregnancy. Anticholinergics are generally Category C, but their contribution to risk in combination with phenobarbital is considered.

Donnatal is generally not recommended during breastfeeding (Lactation Risk L3-L4). Phenobarbital is excreted into breast milk and can cause sedation, poor feeding, and withdrawal symptoms in the infant. Anticholinergics can also be excreted and may reduce milk supply. Risks to the infant generally outweigh the benefits of breastfeeding while on this medication.

Donnatal is generally not recommended for pediatric patients due to the phenobarbital content and the potential for paradoxical excitement or severe anticholinergic side effects. Safety and efficacy have not been established in children.

Elderly patients are more susceptible to the anticholinergic side effects (e.g., confusion, urinary retention, constipation, dry mouth, blurred vision) and CNS depressant effects (e.g., sedation, dizziness, falls) of Donnatal. Lower doses are often required, and close monitoring is essential. Use with extreme caution in patients with prostatic hypertrophy or glaucoma.

• Donnatal is an older combination product; its use has declined due to concerns about efficacy, side effects, and the availability of newer, more targeted therapies for IBS.
• The phenobarbital component contributes to significant CNS depression and has abuse potential, limiting its long-term utility.
• Patients should be educated on the 'dry as a bone, red as a beet, hot as a hare, blind as a bat, mad as a hatter' anticholinergic side effects.
• Due to the long half-life of phenobarbital, effects can accumulate, especially with impaired renal or hepatic function.
• Consider alternative therapies for IBS that do not contain barbiturates or have fewer anticholinergic side effects.
• Patients should be advised to carry identification indicating they are taking phenobarbital, especially if they have a history of seizures or other conditions where abrupt discontinuation could be dangerous.

• Antispasmodics (e.g., dicyclomine, hyoscyamine - as single agents)
• Antidepressants (e.g., TCAs, SSRIs for neuropathic pain/IBS-D)
• Laxatives (e.g., polyethylene glycol for IBS-C)
• Antidiarrheals (e.g., loperamide for IBS-D)
• Guanylate cyclase-C agonists (e.g., linaclotide, plecanatide for IBS-C)
• Chloride channel activators (e.g., lubiprostone for IBS-C)
• 5-HT3 antagonists (e.g., alosetron for severe IBS-D in women)
• Rifaximin (antibiotic for IBS-D)
• Probiotics
• Dietary modifications (e.g., FODMAP diet)
• Behavioral therapies (e.g., CBT, hypnotherapy)

If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.